Vacuum Cups and Suction Cups Vacuum Cup Fittings – Female-to-Male Connection AdaptersPart No. HS38-38M-G Part No. Description A Male Connection Thread B Female Connection Thread Hin. (mm) Lin. (mm) SW (Hex) Fitting Material HS38-38M-G Adapter, G 3/8″ – male to 3/8″ NPT – female G3/8″ 3/8″ NPT 0.45 (11) 1.37 (35) 0.94 (24) Zinc-Plated Steel with Sealing Washer The “G” thread is also known as BSPP, commonly used world-wide for Vacuum Applications. Zinc-Plated Steel with Sealing Washer