Unistrut 1-5/8" Channel Nut, Electro-Galvanized, 1/2-13 - Lot of 100 Genuine UNISTRUT Brand Channel Nut With Regular Spring Nut thread size: 1/2"-13 For use with: P1000, P1100, P2000, & P3000 and All 1-5/8" Channels Silver Finish: Electro-Galvanized Zinc; ASTM B633, Type III