Meet the Batteroo Boost: a reusable sleeve that slips over your batteries and extends their life. It is available for AA, AAA, C, and D-cell batteries. Simply put it on disposable batteries to run your toys, flashlights, remote control for a longer period of time.
Also check out:
Batteroo Boost lets you tap into the remaining energy of your disposable batteries before throwing them away. It works on new and used batteries.
[Source]
Disclaimer: *Our articles may contain affiliate links. Please read our disclaimer on how we fund this site. As an Amazon Associate, we earn from qualifying purchases.