United Brass 1-1/2" NPT blowdown valve with slow-open wheel operation. This valve is rated to 530 psi blow-off. Designed for rugged service of boiler treatment and scale, the integral sliding disc provides a cleaning action that keeps the seating area clear of scale and debris. The cast steel knife gate valve features a stainless steel seat and disc to ensure long-lasting operation. This valve is an alternative to Everlasting brand blowdown valves.