1. SIZING Please Note: Make sure to measure your dog's neck before placing an order. Then refer to the sizing chart: Size M: Adjustable 14.7'17.9'(3746cm), Size L: Adjustable 17'21.8'(4355cm), Size XL: Adjustable 19.5'25.8'(4766cm). Measure your dog's neck with a tape measure at the preferred resting place for the collar. Always allow for adequate breathing room. 2. Premium Material: HighDensity Nylon Webbing, WearResistant and TensileResistant. Substrate: Soft Thickened Diving Material, Breathable and ShockResistant. training collar for dogs,Soft to Wear, More Breathable and MoistureAbsorbent, to a Greater Extent Relieve The Tension Caused By Traction During Actions and Running. 3. Heavy duty dog collars. The Metal dog collar with quick release metal buckle and slider is easy to adjust the comfortable fit and take on/off.quickrelease metal buckle with a smooth locking mechanism.Equipped with a large DRing for quick and easy leash attachment. 4.Practical Design: for mastiff, German Shepherd,Pit Bull,Labrador Retriever,Australian Shepherd,Boxers, Pointers,Puppy,American/English Bulldog,,Siberian Alaskan Husky,Doberman,Rottweiler,Belgian Malinois,Hurley Dog etc.for Small or Medium to Extra Large dogs breeds,and great for dog training, patrol,hiking, walking, hunting, camping, working, runing, jumping, traveling, camping,etc.