Product review (5 stars): Very dendable 220 volt receptacle
This is the best 220 volt receptacle I have been able to find.  I use it with my electric car conversion, and have plugged it in and unplugged at least 100 times and it is still working great, doesn't get warm after charging 5 hours at 20 amps.  Very tight spring fit with the Pass and Seymour 3861CC5 Angle 3 pole 50 amp male plug.