![Retaining Ring for Proof Meter](http://farmtractorrepair.com/cdn/shop/products/2021_06_29_Products_JH_05223_Web_{width}x.jpg?v=1625164279)
Use this retaining/snap ring to hold your proof meter adapter into your pump. This snaps onto the adapter near the cable end.
Applicable to round piston pumps: Ford NAA, 600, 700, 800, 900 or Ford 2000 and 4000 tractors with four cylinder engines.