Function Partial ion plated Sapphire Glass with non-reflective coating 50-meter water resistance Case / bezel material: Stainless steel Stainless Steel Band One-touch 3-fold Clasp Solid Band Illumination Index (Black light LED) Afterglow Regular timekeeping Analog: 3 hands (hour, minute, second), 3 dials (date, day, 24-hour) Accuracy: ±20 seconds per month Approx. battery life: 3 years on SR621SW (Analog) 3 years on CR1616 (Light 9 [sec/day]) Size of case: 39 × 34.1 × 10.8 mm Total weight: 94 g