Ballistic Overreach Boots Durable and quick wrap style: These bell boots are designed to withstand the wear and tear of everyday use, making them a reliable choice for horse owners. Durable Ballistic Nylon Binding is constructed with Ballistic nylon, making these boots extra durable. Double Hook and Loop Double hook and loop closures keep boot securely in place. Ultrashock Lining Ultrashock lining absorbs energy from overreaching and protects the vital areas of the hoof, cornet band and bulbs of the heel. No-turn knob The soft no-turn knob keeps the boot from spinning. Sizing Chart Small Horse Height (in hands) :13-14 | Pastern Circumference: 8" | Boot Height: 4.25" | Bottom Boot Circumference: 13" Medium Horse Height (in hands) :14-15 | Pastern Circumference: 8.5" | Boot Height: 4.25" | Bottom Boot Circumference: 13.5" Large Horse Height (in hands) : 15-16 | Pastern Circumference: 9" | Boot Height: 4.5" | Bottom Boot Circumference: 15" XL Horse Height (in hands) :16-17 | Pastern Circumference: 10" | Boot Height: 4.75" | Bottom Boot Circumference: 15.5" XXL Horse Height (in hands) :17-17.2 | Pastern Circumference: 11" | Boot Height: 4.75" | Bottom Boot Circumference: 16.5" XXXL Horse Height (in hands) :17.2+ | Pastern Circumference: 12" | Boot Height: 4.75" | Bottom Boot Circumference: 17.5" Note Ballistic Overreach Boots should have no overlap when applying them to the hoof because of the NO-TURN knob. Additional note Sizes are based on averages. Because each horse is different, always measure your horse to be certain you are purchasing the correct size.