Measure your pets neck to select the ideal size. The X-Small Collar will fit a neck measuring 8-12 and is finished 1/2 wide. Small fits 11-16 finishing 3/4 wide. Medium fits 14-19 finishing 1 wide. Large fits 18-26 finishing 1 wide. The leash is 5 long, finishing the width of choice of collar size. The name was inspired by the scruffy, lovable dog from The Wizard of Oz!