Just purchased a Gaffrig drive shower a Bravo I. Seems fairly simple but I do have a question. When drilling the holes in the finn (1/2" for the pickup & 1/4" for the mount screw), what kind of metal is the fin made out of and do I need to treat the drilled holes with any sort of corrosion protection?

Thanks for any help.

The plate/fin is made of an aluminum alloy. I would treat the holes with some primer and touch up paint.