I have an older HP12c that uses the button style batteries, but it's been awhile since I got batteries and now I'm seeing two very different button batteries recommended and it looks like these are very different batteries and I don't wish to damage my still working calculator.
Please, if you are not going to use the calculator for some time, remove the batteries, because in contact, in addition to flowing millivolts, can deteriorate and damage the interior of the calculator. Also periodically check the status of them, while using the calculator. According to the Rules of Good Art, it is recommended to clean the poles before installing them, with an appropriate liquid or ethylic alcohol (pharmaceutical use 96%). Also, the contacts of each one, in its housing.
Kind Regards !. Have a nice day !. @Maké (Technical Advisor Premium - HP Program Top Contributor). Provost in HP Spanish Public Forum ... https://h30467.www3.hp.com/