Hello!Welcome to our store Description:Special functions: luminous, week display, alarm, lighting, speed measurement, chronograph, month display, moon phase, calendar, 24-hour indication Waterproof performance: life waterproof Movement type: electronic Strap material: PU Mirror material: plexiglass mirror Display type: number Style: sports Case material: plastic Package include:1Pcs Color :Black/Blue/Red/Green Size:Diameter: 55mm Material:Stainless There are 2-3% difference according to manual measurement. please check the measurement chart carefully before you buy the item. 1cm=0.39 inch,1 inch=2.54 cm
