If you are a military enthusiasts, or you just need a service dog, or you just want to train your dog well, you will need this dog harness. The dogs like playing in the dirt, then a washable harness will fit your need. The molle and velcro make the harness adjustable, you can adjust it into the size you like. And the material is soft and the harness is designed well to prevent chafing on your dog's neck. The harness has nylon grab handles and metal leash anchor points at the end of the neck and rear, which help you get great overall control over your dog. At the meantime, you don't need to put forth your strength to control your big dog. It will be helpful for you. Sizing Chart(Size/Cm) S Chest Girth:40-55, Neck:20-32, Back Length:33, Width:30 M Chest Girth:46-79, Neck:26-42, Back Length:41, Width:34.5 L Chest Girth:51-90, Neck:29-48, Back Length:48, Width:38 XL Chest Girth:56-99, Neck:31-51, Back Length:53, Width:43 The measurement allowed error is +/-1-3 cm.