ANVER Vacuum Cups and Suction Cups For Cup Sizes OC8-24 through OC12-36 Electro-Less Nickel Plated Brass OCF1-18F-G fitting screws directly onto the SLSA-2 Suspensions. Additional fittings for cup sizes OC8-24 through OC12-36: G 1/8″ Male and Female Thread Fittings (BSPP Straight Thread) 1/8″ Male and Female Thread Fittings (NPT Tapered Thread) OCF1-18M-G OCF1-18M-NPT OCF1-18F-NPT The “G” thread is also known as BSPP, commonly used world-wide for Vacuum Applications.