- Seiko 4R36 Automatic Winding - Stainless Steel Casing - Lumibrite on hands and indexes - Hardlex Mineral Crystal - 24 Jewels - Day/Date Display - Water Resistance to 100 meters - Case Diameter:42.5mm From Seiko's 5 Sports Collection. With a stainless steel Rose Gold-Tone finish, Day/Date display, and a Hardlex Mineral Crystal cover.