Introducing the OnGuard RockSolid a state-of-the-art bike lock designed for maximum security against determined thieves. Utilizing advanced materials and technology this lock features a robust shackle and innovative locking mechanisms to create an impenetrable barrier.X4P Quattro olt locking mechanism secures the shackle at four points for enhanced protectionZ-Cylinder is bump-proof and resistant to picking pulling and drilling15mm hardened steel shackle coated for resistance against angle grinders prying and jackingWeather-resistant features ncluding a centered keyway all-metal end caps and an automatic keyway cover to extend durability