The Pearl CA-100 hoop-mounted cowbell holder is equipped with non-marring rubber jaws that rotate to fit the contour of your drum hoop. You get slip-proof clamping power regardless of bass drum size! The knurled "L" shaped rod fits all standard 3/8" brackets and is adjustable front and back, left and right for perfect placement. The "L" arm is held securely by a cowbell-style eyebolt clamp system.