Genuine OEM 18V One, Lithium Ion Compact Battery for Ryobi Cordless Power Tools. COMPACT DESIGN: This compact Ryobi 18V Lithium Ion battery gives you lighter weight for improved tool handling. LIGHTER WEIGHT than most other batteries in this system prevents user fatigue. ONE+ COMPATIBLE: This battery works on all One+ compatible Ryobi power tools, from the string trimmer to the reciprocating saw to the drain auger. IMPROVED BATTERY LIFE over older NiCad models. Up to 4x more runtime. FADE-FREE POWER: Don't worry about your tools getting weaker as the battery drains. With this, you'll be able to work at full power until the juice runs out. If you have Ryobi tools, you need Ryobi power. With the P102 18 Volt Lithium Ion battery pack, you'll have the ideal combination of lightweight design and long lasting power for a variety of applications around the home or workplace. Its power is up to four times greater than older NiCad models. Even when their power is low, these batteries will perform at their maximum power until completely drained. You, also, will not be drained. With this battery's light weight, you'll likely be able to work with decreased fatigue. Whether you want to replace your older NiCad batteries or have an extra on hand, the Ryobi P102 is your best bet.