Duracell Pre-Charged rechargeables are the latest in battery technology offering the best of both worlds. Ready to use from the pack & rechargeable thousands of times. Duracell Pre-Charged batteries have a very low self-discharge, meaning they retain 95% of their charge in the pack for up to 5 years. Duracell's DURALOCK technology means these batteries are guaranteed to stay powered for up to 5 years* when not being used. This huge leap forward in battery technology has been made possible by improvements in the purity of ingredients & upgrades to the construction of the battery cell meaning less power is lost when in storage. Ready to use out of the pack Staycharged for upto 5 years Upto 65 hours use in a PC mouse.