• For a wet block position • Material: Brass • Fits: Contol Blocks 300 & 500 series • Model(s) This Part Fits: Cartridges, Handpiece Control Block 300 Series (38.1831.00), Handpiece Control Block 500 Series (38.1776.00) Includes: • Retaining Ring (RPI Part #ADR240) • O-Ring (RPI Part #RPO312) • (3) O-Ring (RPI Part #RPO303)