BLS 4000next series – one of our best seller reusable devices BLS 4000next half-mask is a reusable device for nose and mouth protection with b-lock connection. Disassembled and reassembled in less than 1 minute, it facilitates cleaning and maintenance after each use. It is available in two sizes and two materials and is equipped to protect everyone's breathing from gases, vapours and toxic particulates. Don't miss all its opportunities.