The Althon PHA-G HDPE Hand stop gate is a simple manually operated valve for small dimension openings and low pressures. Manufactured in HDPE with an EPDM Seal the Hand Stop gate is available to suit 150, 200, 250, 300, 400 & 500mm Dia. openings. Above this size Penstocks are a better option because of the weight. Maximum on and off seating pressure is equal to the height of construction.