The Advantage 1000 Full-Face Respirator has a wrap-around flexible lens that offers a comfortable fit with increased vision. Weighing 40% less than conventional full-face respirators, it is constructed of black Hycar rubber for maximum chemical permeation resistance. The Advantage 1000 comes complete with Nosecups, Identification tag, and mechanical speaking diaphragm for short range communications. In the case of serious biological threats such as anthrax, the mask will only give some protections to the user, but a full-protective suit is the only way to guarantee protection from significant exposure. User should not expect to be able to stay in an affected area for any period of time. The gas mask simply buys more time to get out. What Size Should I Get? Being very adjustable, 85% of adults use medium. Small is for adults with very small heads, Medium for most faces and Large for adults with very large heads.