Review on INNOVA 3619 Compression Tester Extension by Kevin Barbon

As mentioned in the first review, the lack of a one-way valve will affect your count by adding volume in the line. I have used this product in the past. 2 years wondering why my numbers were always 30psi lower than without the extension. The first reviewer explains why. For example, I have a 1979 MG Midget. When used with an extension I saw 90 psi numbers on all 4 cylinders. When I removed the extension, my KD Tool compression gauge showed a steady reading of 130-140psi. I could never understand the discrepancy until I read the review for the first time. Reviewer. I bought it in 2014 so it's too late to get my money back but maybe I can save you from wasting yours - this product is useless.