And I have got to say, if your worried that it won't make that big of a difference, I am now able to stabilize my smoker at 180* for twenty minutes.
The 180* is the bottom prob and the 172* is the upper. Since the smoker was stabilized I didn't feel the need to go longer than 20 minutes.
I'm sure at that temp of 180* I will have problems with blow out, but the difference is huge!
If your having the same problem, give it a try. With all the parts it was about $30, well worth it!