A respirator 15 has a harness 10 that allows the respirator body 20 to be conveniently disposed beneath a wearer’s chin when not in use. A shuttle usable with the rack includes a first cart movable along the aisle and a second cart configured to be carriable by the first cart and to be movable along a row. The neighboring sample values are analyzed and from that a statistical value is formed. The strengthening element has bracket sections positioned below respective ear portions adjacent the back head portion.