Martingale dog collar, made with 3/4 inch lightweight adjustable biothane. Slips over the head and adjusts with tri-glide slide for ideal fit. The martingale collar allows for a looser fit until pressure is applied to the d-ring, tightening the smaller ring, providing increased control and security. Available in Lilac and Black, matching leashes also available in traditional biothane. Disclaimer: I have tested these products on various types and sizes of dogs and crafted them with care, but due to the handmade nature of my products I cannot make guarantees regarding their durability. These products are made by hand and not in a factory so there may be some slight variation between products. Please use at your own discretion and judgement, always use with supervision.