How do you measure for one of our harnesses? Just give us the measurements for the following (if you still can't figure it out, give us a call). Measure Between Discription A - B: around the base of the neck A - C: between the withers, down at an angle to the last rib B - D: top of breastbone, down chest, between the front legs and up the side to the base of the tail Our standard sizes - in inches Size Neck Length Size Neck Length Small 16 28 Large 19 31-32 Small/Long 16 29 Large/Long 19 33 Medium 17.5 29-30 Large/Large 20 31-32 Med/Long 17.5 31 X-Large 21 33-34 Med/Large 20 29-30 X-Large/Long 21 35 Standard Harnesses - We start with quality 2000 lb. nylon webbing and fleece padding, a material that is very light weight, holds very little moisture and dries quickly. These harnesses are made to last and are great for training or racing in any season. We have exceeded the standard in harnesses by providing a unique spiral folded piece designed to resist cupping (doesn't have that sharp point that can poke into a dogs chest). Extended padding is now standard on all harnesses.