... conductivity 3.Closed-cell flexible 4.Fire proof, MoistureproofBellsafe-flex adopting NBR/PVC as the main raw material, is an environmental product ... products are balck,with sheet,tube two types. Usage :Bellsafe-flex (Class B1 )is widely used in heat preservation and insulation ... foam, fireproof apply in HVAC system Specification: Main material : NBR/PVC ID size:1/4", 3/8", 1/2", 5/8 ...