T Series Perpetual Calendar Never miss a birthday or anniversary again. A Timex T-Series Perpetual Calendar watch gives the correct time and date, every hour, every day, year-after-year. And it's not just water-resistant, it's excuse proof. INDIGLO Night-Light Perpetual Calendar Always Displays Correct Date Day and Date Feature 7 Year Battery with Free Replacement Offer Stainless Steel Case Genuine Leather Strap Water-Resistant to 100 meters Mineral Glass Crystal Brushed and Polished Finish Bat