2 stroke testing equipment.

[Mike McNabb]

I own TWO compression gauges. One is a $20 tapered ‘push & hold’ model. The other is an $80 screw in version. Both have Schrader valves, built-in, to hold the pressure.

 

[Breckinridge Elkins]

As has been noted (read the whole thread) the Schrader valve used in the compression tester must open at very low pressure, perhaps 2 PSI or so. The valve used in a standard tire application may be 10+ PSI or perhaps even a bit higher. I believe they are color coded to help identify the "pop off" pressure; the ones that I bought from Snap-On are white.

Mark

They are also sold for SCUBA applications. I bought some from a guy on eBay. Like yours, the ones I got are white.