a innovative sliding valve used in paintball gun or other compressed gas propelled firearm , wherein a portion of the valve body where air is exhausted is reduced in size to allow pressurized air to exhaust more quietly around the valve body by feeding into the air exhaust apertures formed on an extended wall of valve body . because the air pressure is balanced between two equal , or nearly equal , sized o - rings on a central spindle , the valve can be opened more smoothly and quietly , and with less opening force . further , because the exhaust o - ring is contained with apertures and seals against the escaping air , with the resulting compression of the o - ring away from the sealing surface , the o - ring is held in place , and cutting and wear of the o - ring is substantially reduced .