Exterior: Brilliant hard titanium and sapphire glass Back: See-through back 4-screw fixed back cover Glass material: Box-shaped sapphire Coating: Internal anti-reflective coating Lumibright: Yes (hands and indices) Case Size: 43.0 mm (width), 50.0 mm (height), 15.6 mm (thickness) Band width: 23mm Band material: Rubber Clasp: One-push three-fold closure Movement: 9SC5 Instructions Driving System: Mechanical, self-winding (with manual winding) Duration: Approx. 72 hours at maximum winding Static Accuracy: +5 sec. to -3 sec. per day on average Accuracy measured under the conditions of 6 different positions and 3 different temperatures before shipment from the factory in accordance with Grand Seiko's own standards. It differs from the accuracy (portable accuracy) under the environment in which the watch is actually used by the customer. Also, due to the characteristics of mechanical models, depending on the conditions of use (carrying time, temperature, arm movement, strong shocks or vibrations), the accuracy may exceed the aforementioned range. Portable accuracy: +8 to -1 sec. per day Water resistance: 20 atmospheres Antimagnetic: Yes Other: Yes Screw lock crown Metal Allergy Resistant Number of jewels: 60 Stopwatch function (30 minutes and 12 hours).