1. Assemble the tools You will need: a) New CR2032 Battery b) Soft surface to protect face c) 50p coin to open back d) Your watch ! 2. Hold steady Hold the watch face down with watch straps out of the way to allow clear access to the back of your watch. 3. Unlock cover Insert the 50p coin and press firmly and rotate anti-clockwise. The cover will turn and rise slightly when it is opened. Check condition of the cover O-ring and that it is undamaged. 4. Inspect contacts Remove old battery and check that contacts are clean and undamaged. Model 47 and 48 have a coil spring contact whereas the 44 and 45 have leaf spring contact. Take extra care not to damage the upper contact. 5. Insert Battery Insert replacement battery negative side down (+ upwards) . The watch should reset and bleep. IMPORTANT: ensure the side contact clips over the battery as shown. Replace the cover by reversing step 3 6. Reset and Calibrate Reset the watch (by pressing all four buttons on the model 44 and 45) if necessary and recalibrate time, compass, barometer and altimeter to local conditions. If the watch does not restart correctly, remove the battery and wait 30 seconds before re-inserting it.