Two magnetised ball bearings rotate around the watch face in separate, recessed guides: one around the centre of the watch face for the minutes and one around the outside of the watch face for the hours. Materials Case: alloy unibody dial Front: alloy Strap: stainless steelQUARTZ Swiss quartz movementDIMENSIONS Diameter 40 mm / Thickness 10 mmWARNINGS Adjustable clasp for wrists 6 ¼ - 8 ½ inches (159 - 215 mm) in circumference, strap width 20 mmBATTERY Button cell Renata 371WARRANTY Full 365-day warrantyNOTE: Although our watches are designed with highly durable materials, it should be noted that they are not completely scratch resistant. ※Please avoid bringing the watch close to magnetic fields (such as magnets, mobile phones, refrigerators, computers, etc.), as the magnetic field may cause inaccuracies or cause the watch to stop temporarily.IMPERMEABLE AND SHOCK RESISTANT This Magnetic Wrist watch will easily withstand brief contact with water, such as being caught in the rain or washing your hands. It is not intended for water immersion or high-intensity sports.