The Nike Triax 50 watch is a sports-style watch for both men and women that feature an oval watch face and a diagonal display. The band is made from polyurethane and the dial window is mineral based. The watches can be purchased online or at authorized Nike retailers and offer standard day-date display and water resistance. As with almost all watches, the watch battery in the Nike Triax will eventually need to be replaced, requiring the use of a case back wrench (available at many watch repair stores) or a standard screwdriver.

Set the watch face-down on a soft surface, such as a towel.

Use the flat edge of a standard screwdriver to lift open the back of the watch by placing it in the indent on the side of the watch and lifting up.

Lift out the old watch battery and set a new one in its place. The old battery can be used as a guide to purchase a new watch battery. Watch batteries are available at most grocery stores, drugstores or watch repair stores.

Set the case back on the watch.

Align the indent on the case back with the indent on the side of the watch. Press gently into place.

Reset the watch, if necessary.