Silicone Breathing Mask 1. Silicone tube pass by FDA .LFGB.SGS.UL 2.Tube is ... good stability 3.Size can be orde Breathing mask Material NBR, NR, EPDM, FKM, SBR, Silicone, Neoprene or Custom Size According to the ... 300 workers; 3.Good entertainment center and accommodation for workers Silicone Breathing Mask