Scubapro A700 Second StageThe A700 offers effortless inhalation and an ease of exhalation that is unmatched in a precision handcrafted, full metal compact package Air balanced valve smooths out the inhalation effort at varying depths and supply pressures. Rugged full metal case, front cover and valve housing (barrel) are able to with stand years of aggressive diving. Metal construction enables the use of a larger diaphragm inside a compact casing, increasing breathing