- Wide compatibility: three expander sizes fit 1-1/8" to 3-1/2" ID thin-wall pipe. - What it does: quickly and easily straighten pinch marks and widen pipe openings; repair damaged pipe ends. - Size details: Small expander 1-1/8" to 1-3/4"; Medium expander 1-1/2" to 2-1/2"; Large expander 2-1/8" to 3-1/2"; includes 6 additional o-rings. - How to use: suitable for all thin-walled tubing 1-1/8" to 3-1/2" ID. Use with hand ratchets, breaker bars, or hand wrenches. Do not use electric ratchets to avoid damage. - Premium quality: carbon steel construction for strength and durability; rigorously quality inspected; designed for professional mechanics and personal repairs. - Practical applications: restore pinch-marked exhaust pipes, widen openings to fit replacement sections, and reshape or repair damaged tailpipe ends for reliable joins.