Review on INNOVA 3619 Compression Tester Extension by Stephen Thomas

DO NOT USE FOR COMPRESSION TESTING! You can use it for leak testing. The compression tester extension MUST have a one-way valve on the tip (if you look at the compression tester with the hose or extension that comes with the kit you will see the valve in the tip). This product is just a hollow tube with no valve (at least in the one they sent me). This means that its internal volume adds to the volume in the cylinder when the piston is at the top of its stroke, and the pressure is released again when the piston goes down, rather than holding the pressure in the tube. As a result, your compression gauge will read a much lower pressure than the actual compression pressure, especially on smaller engines. I gave it two stars instead of one simply because it was useful for leak testing.