OpTB™ Trunnion Mounted V-Notch Ball Valve - Trunnion Mounted V-Notch Ball Valve. The OpTB is no longer limited to a full-port option and is available in a reduced-port API 607 Fire Safe V-Notch Ball Control Valve configuration that effectively adds throttling capabilities to a traditional, proven three-piece on/off ball valve design. This is an ideal valve for throttling applications in the Midstream Oil & Gas industry where pressure classes and differentials extend beyond the capabilities of the OpVEE.