This revolutionary patented product is the first and only device on the market which allows for connection directly to the chin strap ends of a motorcycle helmet for easy carrying. No more struggling with bungees, speciality back packs, scratched helmets/fairings. Caddystrap makes it possible for you to conveniently connect your helmet to your bike. Works with helmets equipped with the D ring enclosure system . Full face, modular and some 3/4 helmets. Works with removable seats single or double. We recommend measuring your seat and referring to size chart before purchase to find the correct fit. PLEASE refer to 1)VEHICLE LOOK UP or 2)Size chart (measure) -place helmet in the optimal location on your seat -take note of the chin strap locations on each side -remove helmet and measure the circumference of the seat of the noted locations -refer to size chart