1.SIZE: 2.5mm diameter link x 19.7" inch length; for max neck girth 17.7" inch Professional dog trainers recommend our chain slip collar, Our professional choke dog collars are safe and effective tools gentle to firm pull allows this collar to control your dogs behavior easily, great ideal for gentle effective correction. Our high-quality Choke Chains have smooth, rounded edges for superior comfort, smooth operation, and safety. No sharp points or rough edges to chafe skin or snag fur. Ruggedly constructed of electronically welded steel for strength and chrome-plated for durability and shine. Its also chew-proof and perfect for your rough and tumble pup.big aggressive canine dogs. All professionals state: Please measure your dog's neck and add 2 to 4 inches for a proper fit. A choke chain that is a little long will work just fine, larger than the dog's neck measurement, and hang loose (too big is better than too small) This is a Choke Chain Dog Collar. Made of the finest polished chrome plated, double-welded steel links. Will not rust, tarnish or break. The chain links are terminated on each end by a polished chrome plated, welded O-ring. These collars are sized by the total length of the collar, including the O-rings. The collar should fit loose around the dog's neck, and fit over the dog's head. Great training aid and control collar. For training purposes, the collar should be 3" to 4" larger than the dog's neck measurement, and hang loose (too big is better than too small). Feature: 1. High quality stainless steel,strong and heavy duty. 2. Smooth, rounded edges,skin-friendly and safety to operate. 3. Silver chrome plate, will not rust, tarnish or break Specification: Material: Stainless steel Color: Silver Size(Diameter*Length): 2.5mm*19in, 3mm*21.6in, 3.5mm*23.6in, 4.0mm*25.5in Package contents: 1pc* Stainless Steel Dog Chain