Sight Plug, Body Material Brass, Connection Type Pipe Threads, Window Material Glass, Seal Material Buna-N, Reflector Material Stainless Steel, Window Features Reflector, For Liquid Clarity Clear, For Fluid Type Liquid, Thread Gender Male, Thread Size 3/8 In.-18, Hex Width 3/4 in, Pipe Size 3/8 in, Thread Type NPT, Window Diameter 11/25 in, Maximum Operating Pressure 100 psi, Maximum Operating Temperature 180 Degrees F, Body Material Finish Cold Finished, For Use On Gear Boxes/Reservoirs