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2004 Audi A4

Universal gear includes car amplifiers, subs, and other products that do not install in a specific location or require fitment to integrate with a vehicle.

Universal-Fit Audio for 2004 Audi A4

When thinking of universal gear, we consider products like a car amp that gives more power to your speakers or subs, cell phone chargers, equalizers and sound processors, rear-seat entertainment and video monitors, as well as dash cameras.

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The Install Bay SR8

MDF 3/4" Spacer Rings for 8" Speakers (Pair)

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MDF 3/4" Spacer Rings for 8" Speakers (Pair)

• 8" Speaker Ring
• Made from 3/4" MDF
• Perfect for Custom Fiberglass Enclosures

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3
List price $18.99
-11% $16.99

In stock

Only 2 Left!

• 8" Speaker Ring
• Made from 3/4" MDF
• Perfect for Custom Fiberglass Enclosures

Install Bay F6N075BK

3/4" Self-Wrapping Split Braid Sleeving, Black - 50FT

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3/4" Self-Wrapping Split Braid Sleeving, Black - 50FT

• 3/4" split-braid sleeving
• Protects wires, cables, hoses and more
• Protects against salt water, solvents, automotive chemicals and more
• More flexible than plastic
• Resists cuts and other abrasions

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List price $133.99
-10% $119.99

In stock

Only 2 Left!

• 3/4" split-braid sleeving
• Protects wires, cables, hoses and more
• Protects against salt water, solvents, automotive chemicals and more
• More flexible than plastic
• Resists cuts and other abrasions

Install Bay 3MRVBC

3M Red 22/18 Gauge Vinyl Butt Connectors

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3M Red 22/18 Gauge Vinyl Butt Connectors

• Butt Connectors
• 22/18 Gauge
• Color: Red
• Vinyl Insulated
• Makes Crimping Wires Fast and Easy
• Offers a Solid Connection of Wires

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2
List price $18.99
-11% $16.99

In stock

Only 3 Left!

• Butt Connectors
• 22/18 Gauge
• Color: Red
• Vinyl Insulated
• Makes Crimping Wires Fast and Easy
• Offers a Solid Connection of Wires

Install Bay IB5202

LED Replacement Headlight Bulbs - H5202 Single Beam

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LED Replacement Headlight Bulbs - H5202 Single Beam

• Replacement LED headlight bulbs
• 3.1 inch (78.2mm) total length
• Heat sink 1.26 inch (32mm) diameter
• Good for tight applications
• Compact design doesn’t compromise performance
• H5202 LED Single Beam
• As cool or even cooler than the traditional LED bulbs

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List price $119.99
-67% $39.99

In stock

Only 1 Left!

• Replacement LED headlight bulbs
• 3.1 inch (78.2mm) total length
• Heat sink 1.26 inch (32mm) diameter
• Good for tight applications
• Compact design doesn’t compromise performance
• H5202 LED Single Beam
• As cool or even cooler than the traditional LED bulbs

Install Bay IBR92

USB Voltage Monitor LED Round - Water Resistant

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USB Voltage Monitor LED Round - Water Resistant

• In-Dash Knockout Panel
• Adds USB Ports
• Installs in Dash

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List price $43.99
-11% $38.99

Available

Ships in 10-14 days

• In-Dash Knockout Panel
• Adds USB Ports
• Installs in Dash

Install Bay IBSSR

Panel Mount LED Switch

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Panel Mount LED Switch

• For Ultra-luxury high-end vehicles
• 12-24V universal usage
• Environmentally friendly and flame retardant materials
• Suitable for refit control of all equipment in the car
• Output short-circuit protection, overload protection
• Suitable for installation and use of all 12/24v battery vehicles

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List price $16.99
-12% $14.99

In stock

• For Ultra-luxury high-end vehicles
• 12-24V universal usage
• Environmentally friendly and flame retardant materials
• Suitable for refit control of all equipment in the car
• Output short-circuit protection, overload protection
• Suitable for installation and use of all 12/24v battery vehicles

Install Bay IBR57

Dual USB Knockout Panel with Water Resistant Cover - can be surface or flush mounted

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Dual USB Knockout Panel with Water Resistant Cover - can be surface or flush mounted

• Dual USB water resistant knockout panel
• Mounts in dash
• Includes protective cover
• Uses a 1-1/8 inch mounting hole

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List price $41.99
-12% $36.99

In stock

• Dual USB water resistant knockout panel
• Mounts in dash
• Includes protective cover
• Uses a 1-1/8 inch mounting hole

Install Bay 604

Posi-Lock 20-22 AWG Locking T-Tap-Style Connectors (6-Pack)

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Posi-Lock 20-22 AWG Locking T-Tap-Style Connectors (6-Pack)

• Posi-Lock T-Tap Style Connectors
• Locking Twists Prevent Disconnection
• 20-22 AWG
• Package of 6

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List price $14.98
-33% $9.99

Available

Ships in 10-14 days

• Posi-Lock T-Tap Style Connectors
• Locking Twists Prevent Disconnection
• 20-22 AWG
• Package of 6

Install Bay SLT18

Split Loom Tubing 1/8 Inch Diameter 100 Foot Coil

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Split Loom Tubing 1/8 Inch Diameter 100 Foot Coil

• Split Loom Tubing
• Diameter: 1/8"
• Length: 100 Ft
• Material Type: Polyethylene
• Exterior Finish: Smooth
• Color: Black

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3
List price $31.99
-13% $27.99

In stock

Only 2 Left!

• Split Loom Tubing
• Diameter: 1/8"
• Length: 100 Ft
• Material Type: Polyethylene
• Exterior Finish: Smooth
• Color: Black

Install Bay IBCPLR1

0 AWG to 4 AWG Nickel Plated Gauge Reducer

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0 AWG to 4 AWG Nickel Plated Gauge Reducer

• Wire Gauge Reducer
• 0 AWG to 4 AWG
• Nickel Plated
• Deep Wire Recesses
• Ultimate Power Delivery

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4
List price $12.99
-15% $10.99

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• Wire Gauge Reducer
• 0 AWG to 4 AWG
• Nickel Plated
• Deep Wire Recesses
• Ultimate Power Delivery

Install Bay JW4136

18 AWG Male & Female Water-Resistant Speaker Plugs - Pair

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18 AWG Male & Female Water-Resistant Speaker Plugs - Pair

• Water Resistant Speaker Plugs
• Male and Female Plugs included
• 18 Gauge Input

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List price $25.99
-12% $22.99

In stock

• Water Resistant Speaker Plugs
• Male and Female Plugs included
• 18 Gauge Input

Install Bay IBH8

H8 LED SINGLE BEAM PAIR

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H8 LED SINGLE BEAM PAIR

• Replacement LED headlight bulbs
• 3.1 inch (78.2mm) total length
• Heat sink 1.26 inch (32mm) diameter
• Good for tight applications
• Compact design doesn’t compromise performance

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Universal – fits most vehicles.
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List price $55.99
-29% $39.99

In stock

Only 1 Left!

• Replacement LED headlight bulbs
• 3.1 inch (78.2mm) total length
• Heat sink 1.26 inch (32mm) diameter
• Good for tight applications
• Compact design doesn’t compromise performance

Install Bay IBSSWB

Panel Switch - 6-Pin Winch

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Panel Switch - 6-Pin Winch

• For Ultra-luxury high-end vehicles
• 12-24V universal usage
• Environmentally friendly and flame retardant materials
• Suitable for refit control of all equipment in the car
• Output short-circuit protection, overload protection
• Suitable for installation and use of all 12/24v battery vehicles

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

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$13.99

Available

Ships in 10-14 days

• For Ultra-luxury high-end vehicles
• 12-24V universal usage
• Environmentally friendly and flame retardant materials
• Suitable for refit control of all equipment in the car
• Output short-circuit protection, overload protection
• Suitable for installation and use of all 12/24v battery vehicles

Install Bay IBPS55

55 AMP 12V Power Supply

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55 AMP 12V Power Supply

• 55 Amp Power Supply
• Built-In 4 Stage Smart Charger
• Overtemp Protection
• Deck Mounted Converter
• Max Output: 780 Watts

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Universal Icon Universal – fits most vehicles.

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List price $525.99
-10% $472.99

In stock

Only 3 Left!

• 55 Amp Power Supply
• Built-In 4 Stage Smart Charger
• Overtemp Protection
• Deck Mounted Converter
• Max Output: 780 Watts

The Install Bay SB50

8 AWG High Current Power and Ground Quick Disconnect

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8 AWG High Current Power and Ground Quick Disconnect

•8 AWG Power and Ground Quick Disconnect
• Color is Red
• Makes it easy to remove amps, batteries and other equipment quickly
• Requires 2 pieces to create connection

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6
List price $11.99
-17% $9.99

In stock

•8 AWG Power and Ground Quick Disconnect
• Color is Red
• Makes it easy to remove amps, batteries and other equipment quickly
• Requires 2 pieces to create connection

Install Bay MIBRBSR19

Universal 19mm Black Momentary Red LED Switch with Harness

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Universal 19mm Black Momentary Red LED Switch with Harness

• Black momentary switch with harness
• Rated at 5 amps
• IP67 waterproof rating
• 19mm (3/4") mounting hole size
• Red LED illuminated ring

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List price $24.99
-12% $21.99

Available

Ships in 10-14 days

• Black momentary switch with harness
• Rated at 5 amps
• IP67 waterproof rating
• 19mm (3/4") mounting hole size
• Red LED illuminated ring

The Install Bay SR12

MDF 3/4" Spacer Rings for 12" Speakers (Single)

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MDF 3/4" Spacer Rings for 12" Speakers (Single)

• 12" Speaker Ring • Made from 3/4" MDF
• Perfect for Custom Fiberglass Enclosures

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

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10
List price $16.99
-12% $14.99

Available

Ships in 10-14 days

• 12" Speaker Ring • Made from 3/4" MDF
• Perfect for Custom Fiberglass Enclosures

Install Bay FLX14BLK

1/4" Expandable Sleeving, Black - 200 Feet

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1/4" Expandable Sleeving, Black - 200 Feet

• 1/4" split-braid sleeving
• Protects wires, cables, hoses and more
• Great for automotive, marine or office applications
• 200 feet of tubing included
• Resists cuts and other abrasions

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Universal Icon Universal – fits most vehicles.

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List price $104.99
-10% $93.99

In stock

Only 3 Left!

• 1/4" split-braid sleeving
• Protects wires, cables, hoses and more
• Great for automotive, marine or office applications
• 200 feet of tubing included
• Resists cuts and other abrasions

Install Bay IBWTH12

Waterproof Connectors 12 Gauge - Each

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Waterproof Connectors 12 Gauge - Each

• Waterproof Connectors
• 2C Plug in Connector
• Male/Female
• 12 Gauge

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List price $7.99
-13% $6.99

In stock

• Waterproof Connectors
• 2C Plug in Connector
• Male/Female
• 12 Gauge

Install Bay 3MHST18

3M Heat Shrink 1/8" Diameter Tubing Black

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3M Heat Shrink 1/8" Diameter Tubing Black

• 1/8 inch heat shrink tubing
• Made with polyoefin (black)
• Length: 4 feet

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List price $5.99
-17% $4.99

In stock

• 1/8 inch heat shrink tubing
• Made with polyoefin (black)
• Length: 4 feet

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    FAQ for Universal-Fit Audio & Electronics in 2004 A4

    Q: Can I upgrade or change the Universal-Fit Audio & Electronics in 2004 Audi A4?

    A: Yes this page includes all the best Universal-Fit Audio & Electronics that work in your A4.

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    Modern vehicles often require specific brackets, wiring harnesses, and mounting solutions. A fit guide ensures:

    • You see only parts engineered for your exact vehicle
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    • Installation is smoother, faster, and frustration-free
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    Whether you're replacing a factory stereo or upgrading your entire audio system, the Fit Finder eliminates uncertainty.