Better to have it and not need it than need it and not have it! Makes the perfect Gift for the Guy or Gal who has everything! One size fits most. New/Old stock means that although it’s never been used, blemishes exist. Blemishes can include, but are not limited to: Rust, pitting, oxidation on buckles. Work inside bad smelling environments. Nuclear Biological Radiation threats (NBC). Ages 10 to adult. Each Gas Mask comes with its own sealed and unused standard 40mm filter. One mask and one filter per order. Veteran owned USA small business????