The UNISTRUT P1001 20 HG Back-to-Back Channel Hot-Dip Galvanized | 1-5/8" x 3-1/4" | Silver offers superior durability and heavy-duty framing support. https://www.northstarindustries.ca/products/p1001-20-hg-1-5-8-x-3-1-4-back-to-back-channel-hot-dip-galv?variant=50862135607590&country=CA