The No! Slip Martingale Collar Display contains 24 pieces and includes 2 each of the Martingale nylon collars in 4 colors and 3 sizes. Refer to catalogue for a full listing of included products. Coastal's No! Slip Martingale Adjustable Dog Collar is excellent for dogs that easily slip a regular collar. The unique limited closure prevents the collar from becoming too tight. These martingale collars are great for dogs whose neck and head are close in size, such as greyhounds. "Coastal reserves the right to ship kits incomplete with no substitutions."