Type of product: Air relief plug / bleep nipple Most common size reference: 3/8 inch MPT male screw thread Overall outer dimensions approx: Length of threaded part: Height if stood on thread end: Diameter of thread: Commonly used with: Air bleed tee or elbow with 3/8 inch bleed connection. This is also used with our 50 sq ft in line filter housing assembly. Additional notes: This part works with 2 different size o'rings, 1 is for use with bleed valves and 1 is for use with filter parts.