USB Car Charger Adapter Specification Example for Agricultural Trailers: Sealed Unit
USB Car Charger Adapter Specification Example for Agricultural Trailers: Sealed Unit
This is a worked specification for usb car charger adapter in a sealed unit 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 sealed unit version exists because the duty cycle on agricultural trailers is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually a supplier who changed material without saying so.

Example specification
| Item | USB Car Charger Adapter |
|---|---|
| Application | Agricultural Trailers |
| Version | Sealed Unit |
| Base material | PVC Coated Fabric |
| Controlled dimensions | 3 key dimensions, recorded per lot |
| Tolerance band | ±0.1 mm |
| Finish | powder coated |
| MOQ | 500 pieces per specification |
| Sampling | 10 working days, 3 days per revision |
| Compliance | DOT |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — PVC Coated Fabric, 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
- CNC machining
- gravity casting
- surface grinding
- shot blasting
- rubber vulcanisation
Where this example applies
Programmes that run sealed unit most often specify this build for agricultural trailers. Related applications include scooter fleets, long-haul trucks, export programmes, workshop replacements, trailer axles.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 4.0 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 DOT-compliant build instead of a fresh interpretation.
How long does sampling take?
Samples leave the factory in 10 working days, and each revision round adds about 3 days once you have seen the first piece.
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 testing is included?
Standard lots ship with dimensional and hardness reports. DOT documentation is issued with the shipment when your market requires it.
Tell us the model, the fitment and the quantity and we will hold a production slot for you.



