Connect material evidence to a released constructionWaterproof flexible heater substrate: Material & Des…. Engineering illustration, not a production photograph or test result.Connect material evidence to a released constructionWaterproof flexible heater substrate: Material & Des…Exact grade01Stackup02Geometry03Process04Verification05Keep the drawing revision and unresolved questions visible at every step.A supplier data sheet supports the material choice; it is not build approval.