It's true, some bikes fit on racks better than others, but frankly, you should choose your ride based on what works for you, not on ease of transport. So if you're scratching your head, trying to figure out how you're going to fit your new dream machine onto your hanging Alpha or Beta rack, the Kuat Ubar Bike Frame Adapter is here to help. It attaches to your stem and your seatpost, creating an ideal horizontal mount that will make your life a whole lot easier. The spring loaded action keeps your bike secure, and the length is adjustable, allowing it to fit just about any bike, whether it's best described as pint sized, or positively humongous. Plus, the rubberized hooks protect your bike from unsightly scratches. However, if you're using it on a bike with a dropper seatpost, please use extra caution, because the sliding portion of the post is more damage prone than the anodized finish on most stems and seatposts. The Kuat Ubar Bike Frame Adapter is available in one size, and in one color.