Review on Tool Aid 34020 Compression Adapter by Yuan Walsh

Innovative design allows working with 16mm and 12mm spark plug sockets. Works great with all types of compression gauges as the socket is a standard 14mm spark plug nipple. If you have a pressure gauge with a Schrader valve (relief valve) on the end of the hose, that's a problem. This worked for me because my gauge has an outlet valve on the side of the gauge. Great tool. I would buy this again.