The Keystone Series GR is a resilient seated butterfly valve available in flanged, lugged or wafer body style for any service where drop-tight shut-off and maximum flow area is required. It features a wafer and lugged body design with face-to-face dimension, according to EN 558 Series 20 and API 609 and was designed according to EN 593 and API 609. The seat is field replaceable and fully isolates the body and shaft from the flow. Primary shaft sealing exceeds the pressure rating of the valve and prevents leakage through shaft area to atmosphere. A secondary shaft sealing provides back-up safety.