can't do it... takes a professional... pretty sneaky, donchathink? go to tech support @
www.niketiming.com FAQS: Many of our watch designs use special gaskets that create a seal between the back plate and the watch case. In our experience, when you, or even a skilled jeweler, try to replace the watch battery, the gasket is frequently replaced improperly, eventually resulting in water damage. In addition to ensuring that your watch is watertight, our service centers will clean the components and replace damaged parts. Customer feedback on the price, duration and headache of this process has prompted us to start putting user-serviceable battery hatches in our watches whenever possible.