The harness is designed to give you gentle, comfortable control of your cat or kitten. Patent-pending design allows for a gentle pressure on the leash to cradle your cat, thus, restraining any forward motion without putting pressure on the delicate throat area. Sizes: Small 9" - 11" Girth (Kittens to small cats), Medium 10.5" - 14" Girth (Small to average cats), Large 13" - 18" Girth (Average to Large cats); all are 3/8" Wide.