Replacing a Rado watch battery is easy if done by an authorised Rado dealer. Otherwise, replacing the battery gets tricky. Rados are notoriously finicky when it comes to removing the case back to change the battery. Rados are "watersealed." That is, the case back is fitted with a special gasket to keep out moisture. Rados under warranty will not be honoured for repairs if the battery has been replaced by someone other than an authorised dealer. However, replacing the battery yourself on older Rados not under warranty is an acceptable risk.
Use the case blade to pop open the snap back Rado watch. The battery is a small silver disk held down by a spring on the side or a flat strap over the top of the battery. Wedge a screwdriver between the battery and spring to loosen the battery. It will pop out. If the battery is held by the strap, use a screwdiver to loosen, but not remove, the screw that fastens it over the battery. Use the tweezers once the strap is loosened to remove the battery.
Examine the markings on the battery. It is likely to be a 1.5-volt Silver Oxide or Alkaline battery. It doesn't matter which one you use, although the Silver Oxide battery can handle heavier energy-consuming loads, such as a multifunctional chronograph.
Take the battery to any watch repair shop and get the exact replacement battery. It will cost you a couple of dollars.
Try not to touch the battery with your fingers. Instead, hold the battery with the tweezers, use the screwdriver in your other hand to push aside the spring. Place the battery in its holder. Once the battery is in place, move the strap over the battery and tighten the strap with the screwdriver.
Use the case press to replace the case back. Place the Rado face down on the bottom pad, or die. Ensure that the top pad, or die, is exactly the same size as the case back. Make sure the gasket is flush against the rim of the case. The slightest misalignment will make it impossible to have the case back flush with the case and compromise the seal. Press the case back into place.
Unless you are a watch enthusiast who does his own repairs, the risk of compromising Rado's "watersealed" case back is not worth the risk. An authorised Rado dealer can replace the battery at minimal cost.
Don't force open a case back. If the case back needs to be forced, it means you are doing something wrong.