Squat-Proof Coverage Solutions for Swimwear: Sourcing Checklist for Buyers
Questions to put to any mill supplying swimwear with squat-proof coverage specified.
Capability questions
Ask for the test equipment list and the standards used. The relevant method here is AATCC 183 transmission with photography under 60% extension, and the mill should be able to show recent reports. Because the fabric stays wet, stretched and chemically exposed for hours, target checks are made on a worn sample rather than flat fabric alone.
Documentation
Request the technical data sheet, composition certificate and previous results for opacity above 96% at 30% extension. Consistent paperwork usually reflects consistent process control. Keep AATCC 183 transmission with photography under 60% extension named in the tech pack so every lot is measured the same way.

Mill visit checks
Look at finishing conditions and testing frequency. Problems such as knitted fabric loses opacity when it stretches over the body often come from process drift rather than design. Where swimwear is worn for pool training and beach use, set tolerances around that range of movement.
Commercial terms
Confirm minimum quantity, lead time and the cost impact noted as 3-6% fabric cost for higher density and finer gauge before development work starts. Any change to nylon and polyester knits at 190-230 GSM with high elastane requires re-testing against opacity above 96% at 30% extension before bulk is released.
Warning signs
Be careful where samples perform differently from bulk, or where reports are only issued on request. Past reports from AATCC 183 transmission with photography under 60% extension help the mill reproduce the same recipe on the next order.