Avon B7 Inflation / Deflation Valves. The B7 is identical to the A7 in its inner workings. It offers all the advantages of the A7 but provides a lower and a more snag free design. Its rounded mushroom shaped cap fits close to the chamber. It clamps directly to the chamber material so it does not require a mounting boot to be glued in. Requires no routine maintenance. Color is gray.