The RS561 frame lock has been designed for demanding cyclists who do not compromise on technology and security. At its core is the robust 8.5 mm shackle made of hardened steel, now shaped in a square form to significantly increase resistance against bolt cutters and saw attacks. In the event of tampering attempts, a special rotating mechanism ensures that the shackle locks itself within the lock housing – a detail that makes a difference when it matters. The housing has also been designed for maximum stability: instead of riveted components, a fully welded steel shell is used, completely eliminating side attack points. The RS561 is also fully compatible with TRELOCK's insert chain system, allowing the bike to be secured to fixed objects with a single motion – efficiently, easily, and securely. The construction is complemented by a newly developed high-security cylinder. Its asymmetric milling, protected recesses, and improved coding technology make unauthorized opening attempts nearly impossible.