Black anodized aluminum body Teflon adapter for particular crystal size Easy assembling and disassembling No glue Ring mounts made from black anodized aluminum and Teflon are available for safe and convenient handling of nonlinear crystals. The standard sizes are Ø 25.4 or Ø 30 mm and thickness 10.5, 13.5 or 17.5 mm depending on crystal size.