18-8 / 304 Grade Stainless Steel Solar Panel Mounting Hanger Bolts. SOLD BY THE PIECE. Solar Hardware Bolts Made From 304 / 18-8 Stainless Steel Solar Panel Mounting Hanger Bolt Assembly. 1: 3/8 X 7/8" Bonded Sealing Washer. 1: 3/8 X 1-1/2" Fender Washer. 1: 3/8 Flat Washer. 3: 3/8-16 Hex Nuts. Contact Our Sales Department For Bulk Pricing and Other Sizes.