Product Description Choke Dog Chain Collars, Metal Slip Link Training Heavy Duty Dog Choker Collar Martingale Puppy Collars For XXS XS Small Medium Large Big XL Breed Dogs 【Size】 XXS Length 12-inch for dog's neck max 8-inch, link diameter 1.6mm. Weight about 20g. XS Length 16-inch for dog's neck max 12-inch, link diameter 2.0mm.Weight about 36g. S Length 20-inch for dog's neck max 16-inch, link diameter 2.5mm.Weight about 68g. M Length 22-inch for dog's neck max 18-inch, link diameter 3mm. Weight about 105g. L Length 24-inch for dog's neck max 20-inch, link diameter 3.5mm.Weight about 158g. XL Length 26-inch for dog's neck max 22-inch, link diameter 4mm.Weight about 227g. Please measure the length of your dog's neck before ordering. you can buy bigger one size.If your dog has a large head, it is recommended to buy bigger size. 【Durable and Rust-free】The choke dog chain collar made of alloy steel and chrome plating, won't become rust and tarnish over time. Simultaneously it's sturdy enough to hold your do, yet light enough for his to pick up your cues for his behavior.