●This kit provides the handy collets and expander required to stretch tailpipes before making tight seals to pipes with smaller diameters. ●Collects for a broad expansion range from 1-5/8in. to 4-1/4in. Steel Expander 1-5/8in.- 2in. Collet Steel Expander 2in.- 2-1/2in. Collet 2-3/8in.- 2-3/4in. Collet 2-3/4in.- 3-1/8in. Collet 3-1/8in.- 3-1/2in. Collet 3-1/2in.- 3-7/8in. Collet 3-7/8in.- 4-1/4in. Collet. ●Can be used with an impact wrench to quickly stretch pipes.