K-Edge's Road Clamp-On Chain Catcher prevents the chain from derailing off the small ring to the inside which can result in frame damage. It simply attaches to your seat tube below the front derailleur. Both the clamp and "foot" are made of CNC'd aluminum so you know they're light and strong. And, installation and positioning are easily achieved with the simple design!
Your seat-tube diameter determines the needed derailleur clamp size.