Watts Bonnet Assembly Kit 1/2 in. - 1 in. for 800M2 PVB. This 1/2-1 IN bonnet repair kit for the pressure vacuum breaker, series 008M2, prevents the reverse flow of polluted water from entering into the potable water supply due to back siphonage. It consists of a bonnet and bonnet O-ring, vent spring, hood and hood screws. It is ideal in health hazard continuous pressure applications such as irrigation systems and industrial process water systems where the water enters the equipment at or below its flood rim.