The Twofish Megablock XL is designed to securely attach your large shackle U-lock to your bikes frame. Don't carry that thing around in your backpack, or leave it dangling from your cockpit while you ride. Secure it out of the way and ride unencumbered. Features: A single-point attachment system for large shackle U-locks Attaches securely to most top tubes Works with Kryptonite's New York Fahgettaboudit U-lock, Abus's Granit U-lock series and OnGuard Pit-bull series Specs: Description: Megablock XL