
Three other reviews mention installation difficulties. Solution: You need to cut off the protruding lower lip. All other rings have the same diameter, which ensures a good tight fit. The top ring is also wider so it won't fall off. Doesn't fit a 4" PVC fitting as intended. Why some break and come back. I don't want to change it now as the end is covered in poop.

NANPU Air Drying System With Double Filters And Pressure Regulator Combo For Clean And Controlled Air Supply
18 Review

NANPU 1 FRL Air Filter Regulator Lubricator Combo With 0-150 Psi Gauge, 5 Micron Brass Element, Poly Bowl & Semi-Auto Drain - Metal Bracket Included
20 Review

NANPU Compressed Air Filter Regulator Combo: Brass Element, Semi-Auto Drain, 0-150 Psi Gauge, And More
21 Review

NANPU 1/2" NPT Air Drying System - 5 Micron Particulate Filter, 0.01 Micron Coalescing Filter, Air Pressure Regulator Combo - Semi-Auto Drain, Poly Bowl W/Metal Gauge
23 Review