The Liberty GR20NS is a GR20-Series guide rail base for hazardous-location installations, fitted for XLSG- and XLSGX-Series explosion-proof grinders — an iron base with a non-sparking bronze mating claw, 1-1/4" FNPT guide pipe and discharge threads, and a powder coat finish. Includes a mating flange, an upper rail support bracket, stainless steel bolts, and a heavy nitrile sealing grommet.