Anvil-Strut Wing Fittings are designed to fit with all Anvil-Strut 1-5/8" wide channels. Unless otherwise noted, Anvil-Strut Wing Fittings are manufactured from 1/4" thick carbon steel, 1-5/8" wide, all holes are 9/16" diameter, spaced 1-7/8" on center and 13/16" from the end.