PERFORMANCE STAR STUDS billet aluminum backers for single or 2 ply tracks now available. These are super light and combine the backer and nut in one unit. The machined grooves enhance traction while also engaging the installation wrench. These are top quality and offer superior performance and traction while being stronger than any nylon style backer on the market. Sold in 48 packs- quantities of 2 packs or more include a wrench. This part number is for 2 ply tracks.