For sale is a MSA Gas Mask Type N w/ Window-Cator Canisters Model SW THIS HAS NOT BEEN TESTED OR SET UP IN ANY WAY. I have no idea of the safety or operating functionality of this gas mask and am not set up to test it. It is the buyer's responsibility to employ a qualified engineer to evaluate the safety of this product. DEATH OR SERIOUS INJURY COULD OCCUR if this is used haphazardly or without being first evaluated. This mask is sold is.