... . Tube and socket: Phosphor bronze and brass5. Liquid Filling: With or without liquid, glycerine., silicone oil6. Connection: 1/8, 1/4 ... , 3/8, 1/2, inches BSP, NPT or BSPT7. Type: Bottom or Back( Radial or Axial)8. Scale ranges: Vacuum and compound -1 ...