One thing that I discovered is that you want couplers with at least 4 ball contacts. Look inside the coupler and if you only see 3 ball contacts don't buy them as they will most likely be leakers.
John
~ J Lucas 2006 GMC Envoy 4.2 I6 2023 Ram 2500/Cumins 6.7 I6 2010 Jeep Grand Cherokee (Wife’s) 2002 Silverado 2500 Gas 6.0 1941 Chevy 1/2-Ton 1942 Chevy 1.5-Ton SWB In the Gallery My Flicker Photos!