I just received two Simplex 4903-9219H Horn/Strobes, and I’m trying to figure out the difference between the “regular” -9219 and the -9219H. Does anybody know what it is?
There is a mention of this unit, as well as similar units, on the UL listing page: Login
I looked it up a long time ago, and the “H” refers to devices designed for high-humidity environments. So they probably come with a gasket or something.