
Tritium, or hydrogen-3 is a rare and radioactive isotope of hydrogen. Yes, unlike the "grow in the dark" lumes, it grows by itself! Its half-life is 12.32 years, so by then it might not be as bright as it is now, but it is handy to have something that shines all the time.
"Wait, so is it radioactive?! Is it safe???" Well, let me quote Wikipedia "it is not dangerous externally (its beta particles are unable to penetrate the skin), but it can be a radiation hazard when inhaled, ingested via food or water, or absorbed through the skin." So, don't eat the Tritium!
Brand Name: CARNIVAL
Model Number: 8638
Feature: Date / Day-Date
Feature: Tritium
Case Diameter: 39mm
Case Thickness: 11mm
Case Material: Stainless Steel
Lug-to-Lug:
Crystal: Hardlex
Movement: QUARTZ
Water Resistance Depth: 3Bar / 30M
Bracelet/Strap Type: Metal Bracelet
Clasp Type: Push Button Hidden Clasp
Boxes & Cases Material: Paper
Origin: China
Model Number: 8638
Band Width: 21mm
Case Shape: ROUND