Freeze relief valve?

[Ballvalve]

http://www.grainger.com/Grainger/WATTS-Freeze-Relief-Valve-1RDB2?Pid=search

Sounds too good to be true. Anyone try this?

 

[Valveman]

A lot of things seem too good to be true, but that doesn't mean it isn't true. Good idea, should work. I have done the same thing with and electric valve and a thermostat several times.