Double Flywheel Hollow Watch Automatic Mechanical Watch Calendar Men'S Watch $ 62.54 Product information Movement: fully automatic mechanical movement Strap: original silicone strap Movement: fully automatic mechanical movement Strap: original silicone strap Waterproof: life waterproof Dial length: 43mm Strap width: 20mm Table mirror: mineral strengthened glass Function: hollow Weight: 105g of silica gel Dial thickness: 16mm Strap circumference: 175mm-215mm