I put my new fixture in the other day with no probs. That I figured would be OK, but I originaly wondered how it would last in the mobile application. I now see from these great responces that it should be fine, save the fact that this was a convenience chioce, as well as a "frugal" choice. This will be a lesson on forgoton steps in winterizing, so perhaps any on other replacements, I might just buy for looks; buy for life... . 
