60 Minutes Mechanical Clocking Big Circle Pendulum Timer Reminder Mechanical timer,customized by special machinery,the principle is the same as mechanical watch,without battery,economical and practical Instruction: turn the timer clockwise to zero scale,and then turn it anticlockwise back to the required time. The timer will send out a clear bell at that time When rotating to the end,do not use too much force to avoid damaging the built-in movement During timer operation,do not rotate back and forth to avoid damaging the built-in movement Adjustable from 1 minute to 60 minutes Specifications: Material: external plastic,internal metal Size: 9.3 * 5.2cm Weight: 103g Battery: no battery required Package included: 1 x 60 Minutes Mechanical Clocking Big Circle Pendulum Timer Reminder