SCBS-M8-20-VR NBK Clamping Cap Vacuum Vented Screws with full ball to firmly secure workpiece for Vacuum Devices Made in JapanClamping Cap Screws with Ventilation Hole SCBS M8 20 VR NBK Made in Japan One Screw Characteristics: SCBS VR has a full ball to firmly secure workpiece at the contact point.. Ventilation holes and grooves easily release gas trapped in machines. The thin fluorine coating keeps the ball highly lubricated, even after cleanroom washing. This screw is used to secure work in vacuum devices and vacuum chambers, such as FPD production equipment and