Philip Stein Quartz Stainless Steel and Silicone Casual Watch, Color:Black (Model: PS-DAYNIGHT7) Black chronograph silicone watch and sleep bracelet box set The natural frequencies inside every Philip Stein product that may help balance you during the day are different and unique from the natural frequencies that may help improve your quality of sleep. The technologies in our watches, and sleep bracelets are finely tuned to pick up and channel toward our bodies, specific frequencies that have different desired effects, for daytime or nighttime usage Japanese-quartz Movement Case Diameter: 43mm Water Resistant To 99 Feet