A/C Gauge Knobs
Replacement knobs for the Harbor Freight A/C Gauge set. Mine broke after a few months of use. I didn't have to file or clean anything up to get them to fit, but they are definitely a tight fit.
Gauges:
http://www.harborfreight.com/a-c-manifold-gauge-set-92649.html
30mm total height
6mm hole diameter
13mm hole depth