Advance wafer Type Butterfly Valve (Nylon Coated SGI Disc, Lever Operated), available 50 mm to 200 mm at PN 16. A quarter turn moves the disc through the full stroke, so large-bore lines can be operated quickly without a gearbox in the smaller sizes. Lever operated, so the position is readable from across a plant room. The IS 210 cast iron body is the economical choice at larger bores. It suits steady water service but not lines that see mechanical shock. A wafer body adds almost nothing to the length of the pipe run. The table above gives the price for each size in the range.