Was crusing around freestyle and found they have 2 products called "blackout cloth" one is a 70 denier ripstop fabric with a WHITE! urethane coating the other is a 400 denier witha 3 mil pvc coating. Anybody have any thoughts on its suitability as a bellows material? the one with the white urethane coating doesn't sound good and the pvc may be too brittle for constant folding?