The Seiko Lassale range of watches was introduced in 1981 and features dress watches for men and women. Their most distinguishing feature is their extraordinary thinness. Lassale watches come with a factory warranty that expires if the watch is tampered with. If your watch is no longer under warranty, you can change the battery in a few easy steps. You will know the battery needs replacing when the second hand begins to move in two second increments.

Lay the Lassale quartz watch face-down on the soft cloth. This will prevent it from getting scratched. Remove the watch back. The back will either pop off or screw off. If the back has two grooves along the side, you can slide the flathead screwdriver in under the watch back and apply upward pressure to pop off the back. If your watch has small screws on the back, use the wrench to loosen the screws and remove the head. Watch case wrenches are available from craft and jewelry stores.

Remove the old battery by sliding the flathead screwdriver under it and easing it out. Take care not to scratch any of the components. If you are struggling, use the screwdriver to lift the clip that keeps the battery in place up. Hold it up with your finger. Use the screwdriver to slide the battery out.

Insert the new battery. Use a plastic tweezers to slide it in underneath the clip. Avoid touching the battery with your fingers as oil and salt from your fingers will cause corrosion. Once the battery is in place, replace the watch back and pop or screw it in securely.