This 1-1/4 in series 188A anti-siphon vacuum breaker for irrigation systems prevents the reverse flow of polluted water from entering into the potable water supply due to backsiphonage. It consists of brass body construction with bronze internal trim, chemical resistant silicone seat disc and an atmospheric vent to prevent spilling. It is ideal for low flow non-continuous pressure health hazard installations such as on residential irrigation systems. Maximum pressure is 125 psi.