Sizes: small, medium and large available. Look also at the matching dog lead on amazon.co.uk the red dingo dog harness is a unique design that"s easy to put on your dog, and keeps them safe. There"s just the one snap buckle and all the straps are adjustable. To put the harness on, it slides over your dog"s head and left front leg go through the opening, the strap with the buckle comes up behind the right front leg, then snap the buckle and you"re set! there"s no pressure on the neck, and the lead ring is behind the shoulder blades. The snap buckle, or bucklebone (a registered design) is fantastic and easy to clasp and undo.