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