Product Name: Brass Pipe Cap Material: Brass Color: Gold Tone Thread Size: 1/8NPT Thread Length : 0.31 " =8mm Hex Width :0.51" =13mm Hex Height : 0.51" =13mm Total Size: 13 x 13mm / 0.51-inch x 0.51-inch (W*H) Package Content : 4pcs x Brass Cap 1.THREAD TYPE. This hex head end plug is a brass pipe fitting with 1/8" female NPT threads. 2.MATERIAL.This fitting is made of brass for corrosion resistance, ductility at high temperatures, and low magnetic permeability. Brass can be connected to copper, brass, plastic, aluminum, and welded steel. 3. ADVANTAGE. It has Female NPT threads for connecting to male threaded pipes, creating a tighter seal than straight threads. The round drive countersunk plug has fair vibration resistance and is suitable in low to medium pressure applications. 4.APPLICATION. Generally used in Air conditioning refrigeration, plumbing hardware, hot and cold water supply, air energy water heater, construction machinery, refrigeration equipment, etc.