Freedom Harness Sizing To measure your dog for the Freedom No Pull Harness, take a soft measurement tape and measure all the way around the largest part of the chest, right behind the front legs. Then, you can choose the *smallest* size that still fits your dog. So for example, if your dog’s chest measurement is 28″ exactly, we still recommend that you choose the size Medium, as the front straps will be a better fit. PS The 5/8″ Medium and 1″ Medium fits the same chest measurement range. If your dog’s average weight is 32lbs – 40lbs, choose the 5/8″ Medium. If your dog’s average weight is 40lbs – 60lbs, choose the 1″ Medium. ” Size Chart for Freedom No-Pull Harness Once you’ve measured, received the correct size, and are ready to use this harness, check out this page for tips on Freedom Harness fitting instructions. Collar Sizing Side Release (Buckle Collar) and Buckle Martingale Measurements Use a soft tape measure and measure around the largest part of your dog’s neck. Martingale Collar Measurements Use a soft tape measure and measure the largest part of your dog’s neck AND the smallest part of the neck (usually right behind the ears). This dog collar measurement chart illustrates the 3 areas you must measure in order to select the correct size for a martingale collar. Measurement A: All the way around the head at the largest point Measurement B: Right behind the ears (the smallest part of the neck) Measurement C: Where the collar sits Note: If you are ordering a Martingale Collar, you will need measurements A, B, and C. Use the largest measurement to choose the appropriate size. For Side Release or Buckle Martingale (Combo) collars, you only need measurement C.