A must have for every tack box, this Bit Sizer is a quick, simple and accurate way to figure out what size bit your horse needs. Accurately measures for a properly fitted bit. Molded from durable engineered resins. Fully washable. Measurements range from 3 to 8 1/4. Excellent accessory to have on hand if you have a lesson program, show barn, or sale barn. When new horses are coming in or you're changing bits for training purposes, making sure you are using the correct size bit makes a difference. Mary's offers bit rentals on most of the bits we stock, so using the Bit Sizer assures you're getting the right size to try on your horse or pony.