Timex Marathon Digital Watch 39mm. The 39mm case and black silicone strap come together to complete your new favorite digital watch. Specifications for Timex Marathon 38mm Digital Watch: Manufacturer: Timex Gender: Unisex Band/Strap Color: Black Case Color: White Case Material: Silicone Case Diameter: 39 mm Band/Strap Material: Silicone Wrist Band Type: Strap Package Contents: Timex Marathon 38mm Digital Watch Timex TW5M32600: Marathon Digital Watch 39mm