The 653B-20-40-1 High-Speed Exhaust Throttle Valve features a 0.779 in. (20 mm) nominal inside diameter and a size NW40 ISO-KF flange. A flapper O-ring is included. The 653B's high speed motor and gear/driver assembly provides fast response to a given set point to quickly achieve desired pressure and increase system throughput. High accuracy is attained by microstepping the flapper to give more precise control, and no drift, of pressure at the desired set point. The 653 has sufficient torque to operate sealing valves up to four inches and non-sealing valves to 12 inches to prevent clogging from contamination build-up. The valve body can be heated up to 150°C (using optional sealing materials) for operation in high temperature applications and processes. The 653 has a flapper position indicator to identify valve angle during system troubleshooting, is available in a variety of sizes and flange styles, and is compatible with MKS 651 and 1651 controllers.