Nike as become a worldwide leader in the manufacturing of athletic apparel and accessories including sportswear, shoes, sports gear and timepieces. The "Nike Timing" division specialises in the development of precision watches and stopwatches and has service manuals for every make and model of Nike watches. If your Nike watch lacks a metal circle on the back that houses the replacement battery, you may need to contact your local Nike store or watch repair shop to have the battery changed.
Lay the watch, with the face down, on a microfiber cloth.
Find the metal circle on the back plate of the watch. Feel for the indention located in the centre that is used to open and close the back of the watch.
Place a coin in the indention and turn the metal circle until it reaches the "open" marker. If performed correctly, you should be able to remove the small circle from the back of the watch.
Remove the existing battery and replace it with a replacement battery. The positive ("+") side of the battery should be facing up.
Cover the battery hole back up with the metal circle and use the coin to close the circle by rotating it to the "closed" marker.