Dixon SHD-Series Schrader Pneumatic Male Pipe Coupler SKU Body Size Threads Length SHD2M1 1/4 1/8-27 NPT 1.54 SHD2M2 1/4 1/4-18 NPT 1.72 SHD4M3 1/2 3/8-18 NPT 1.81 SHD4M4 1/2 1/2-14 NPT 1.87