The expandable jaw on the Pearl's Icon Expandable Pipe Accessory Clamp adjusts to accommodate pipe diameters of 1/2" - 1". It creates more room on the main Icon Rail by adding additional mounting points on the rack; attaching to the top of our 1.5" round support pipes securely at two points. Cymbal arms and tom mounts are kept tight, secure, and in their place. Furthermore, its dual-tension clamping design provides non-slip secure settings and is fully compatible with other manufacturer's 1.5" pipes.