Small Expander: 1-1/8″ to 1-3/4″. Type：Exhaust Pipe Expander. Large Expander: 2-1/8″ to 3-1/2″. 1x Small Expander: 1-1/8″ to 1-3/4″. 1x Large Expander: 2-1/8″ to 3-1/2″. Designed to quickly and easily correct dents stuck in muffler, exhaust system, maintenance and installation, applicable to all 1-1/8 to 3-1/2LD thin-walled tubes.