2-Pack Ryobi OEM 40V 4.0Ah Lithium-Ion Battery set OP4040

FUEL GAUGE: You can tell how much of a charge your battery has left, as well as any potential defects, with the onboard LED system, WORKS WITH RYOBI OUTDOOR PRODUCTS: Over 15 tools in the Ryobi 40V line are compatible with these batteries, from string trimmers to lawnmowers, COLD WEATHER PERFORMANCE: These batteries can function at temperatures as cold as -4 degrees Fahrenheit (-20 degrees Celsius)