Baby got back. No, we're not talking ba-donk-a-donk; we're talking stud backers. Premium, aluminum stud backers. We made these double backers 1-1/4" x 2-1/4", for the riders who want to run a tight double row of studs up the center of their track. These 0.180" thick backers are the perfect weight and profile to secure any 5/16" diameter stud. The premium aluminum construction protects against wear and tear.