Yale High Security Open Shackle Steel 51mm Padlock Super-strong and designed to meet high security requirements, this weatherproof padlock has a robust steel body and a shackle crafted from boron steel for extra strength. It also has a rekeyable cylinder which is ideal for maintaining security if your lock is used by lots of people and has a double ball locking mechanism for extra security. Includes 3 keys 9.5mm shackle