CHINA LOCK 63MM TRI-CIRCLE The CHINA LOCK 63MM TRI-CIRCLE is an unrivaled security solution for your home. With its multi-circle design, this lock offers three times the security of a traditional pin-and-tumbler lock. Its 63mm size provides an additional layer of protection that is durable and reliable. Invest in the highest security possible with the CHINA LOCK 63MM TRI-CIRCLE.