If your Armitron has a set of 6 inset notches around the back, as does my Y121E 20/1791F Armitron Diamond, that's a screw-back case that does _not_ pop off or pry off. You'll need a case opener tool, which is basically a small tool with adjustable-gap jaws that fit into two notches on opposite sides of the case and let you unscrew it. Wal-Mart sells this tool for about five bucks, and it'll pay for itself soon enough, as many watches have screw backs, and this will fit most anything you find. Head for their jewelry department and you should find the tool hanging up with the replacement watchbands and batteries.
The case is probably screwed down fairly tight against its O-ring seal, so make sure the tool is seated properly in the case notches, and turn it slowly and firmly counterclockwise to work it loose.
If your watch is like mine, it'll take a #377 cell, but wait until you've opened yours up to be sure.
Y121e is the movement type not model number. I use a Testor's razor knife very carefully with eye protection to pry off the back. If it has notches you need a Jax tool to remove the back. They sell those on Ebay. The other option is to see if Walmart will do it. They only change batteries on watches they sell and they sell Armitron. If you plan on changing batteries out yourself in the future look on Ebay for tools to do it. You may also need a case press to put the back back on. Some are tough and you cannot press the back on by hand. You have to be very specific in describing the type of back before anyone can help you online.
Answers & Comments
If your Armitron has a set of 6 inset notches around the back, as does my Y121E 20/1791F Armitron Diamond, that's a screw-back case that does _not_ pop off or pry off. You'll need a case opener tool, which is basically a small tool with adjustable-gap jaws that fit into two notches on opposite sides of the case and let you unscrew it. Wal-Mart sells this tool for about five bucks, and it'll pay for itself soon enough, as many watches have screw backs, and this will fit most anything you find. Head for their jewelry department and you should find the tool hanging up with the replacement watchbands and batteries.
The case is probably screwed down fairly tight against its O-ring seal, so make sure the tool is seated properly in the case notches, and turn it slowly and firmly counterclockwise to work it loose.
If your watch is like mine, it'll take a #377 cell, but wait until you've opened yours up to be sure.
Y121e is the movement type not model number. I use a Testor's razor knife very carefully with eye protection to pry off the back. If it has notches you need a Jax tool to remove the back. They sell those on Ebay. The other option is to see if Walmart will do it. They only change batteries on watches they sell and they sell Armitron. If you plan on changing batteries out yourself in the future look on Ebay for tools to do it. You may also need a case press to put the back back on. Some are tough and you cannot press the back on by hand. You have to be very specific in describing the type of back before anyone can help you online.