Round plastic backers for Redtip Power Studs have dome shape with perimeter shoulder for added strength. Backers are approximately 1-1/4" in diameter and 3/8" high. Featuring track-side interior recess for weight reduction. Special anti-freeze polymer formula resist breakage. These are very tough backers and reduce overall weight of stud installation. The high dome shape provides higher stud shaft support, thus decreasing the effective bending stresses in the stud. This is a huge advantage for longer studs, which are more prone to bending. Fits 5/16-inch studs. Note: These will not work with 0.875 studs. Do not over tighten or install with impact tools. Follow instructions on package. Available in six colors: black, purple, red, blue, yellow, green or orange. Pack of 24.