This collar's color is definitely a consideration. It could look great or not so great depending on your dog's coloration.
Light Chestnut Chain Martingale Collar (12 3/4")
1 1/8" tapering light chestnut "English" bridle leather chain martingale collar with small chrome brass 3 ring assembly chain; 12 3/4" inner circumference
Because the chain martingale collar needs to slip over your dog's head, you need to measure the largest point BEFORE it slips onto and over the ears. Using a flexible tape measure is helpful. The measurement around the head will be the inner circumference or inner measurement of the collar. Be careful to avoid fingers under the measuring tape. Remember that it is easier to slide a collar over the head and onto the neck than to pull it off.