Car Audio System Specification Example for Aftermarket Retail: Standard Replacement
Car Audio System Specification Example for Aftermarket Retail: Standard Replacement
This is a worked specification for car audio system in a standard replacement programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The standard replacement version exists because the duty cycle on aftermarket retail is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually premature wear on the first batch.

Example specification
| Item | Car Audio System |
|---|---|
| Application | Aftermarket Retail |
| Version | Standard Replacement |
| Base material | Zinc Plated Steel |
| Controlled dimensions | 3 key dimensions, recorded per lot |
| Tolerance band | ±0.2 mm |
| Finish | powder coated |
| MOQ | 3,000 pieces per specification |
| Sampling | 10 working days, 3 days per revision |
| Compliance | SAE J431 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Zinc Plated Steel, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.

Processes involved
- injection moulding
- rubber vulcanisation
- anodising
- sintering
- ultrasonic cleaning
- gravity casting
Where this example applies
Programmes that run standard replacement most often specify this build for aftermarket retail. Related applications include three-wheelers, construction equipment, fleet maintenance, scooter fleets, light trucks.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 2.5 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the SAE J431-compliant build instead of a fresh interpretation.
What is the minimum order quantity?
The standard MOQ is 3000 pieces per specification. Mixed sizes inside one shipment are accepted once the total reaches that figure.
How is packing specified?
Individual packing, inner box quantity and carton marking are confirmed at quotation stage so the cartons arrive ready for your warehouse.
What happens if a lot fails inspection?
The lot is re-inspected against the golden sample, and replacement pieces ship on the next available booking at our cost.
Share a sample or a drawing and we will quote against a written specification, not against a photograph.



