For fastening to wood under-structure.  CorruBracket always requires four(4) screws to mount properly to the roof under-structure.

5/16” Cupped HWH is manufactured from a strong ZAMAC zinc-aluminum alloy. The head is molded, it is not a cap. The molded head encapsulates the EPDM washer, which fits neatly and conforms to the inside of the mold.