Anyone ever hear of a HL180F? I pick up the one recently listed on e-Bay only because it peaked my interest. It's identical to the 175 but has a phenolic diaphragm. Could it be like the 2482 which is suited for exterior use? The bolt bolt pattern of the diaphragm is identical to the 175, unlike the bolt pattern of the 2482 which is larger than the 2440. Google wasn't much help nor could I find anything here.

Thanks,

Eric