These two LFP 123A lithium-phosphate rechargeable batteries"which retain approximately 50% of their original capacity even after 500 charging cycles"will power SureFire illumination tools that use disposable 123A lithium batteries. The runtime of these LFP 123A lithium-phosphate batteries is about 50% of that provided by disposable 123A lithium batteries; maximum output levels are typically not affected. Use of these rechargeable batteries can result in a cost savings over time, depending on usage habits. Recharge only with AC/DC charger included with SF2R-KIT01, sold separately.