Mighty Mule 12-Volt Battery for Mighty Mule Automatic Gate Openers  (FM150) 12-Volt, 7 amp-hour battery. Compact, maintenance-free battery fits within all standard control boxes. Battery approved for use with MM560, MM562, FM500, FM502, SL1000B and SL2000B operators, not for use with Mighty Mule FM200, FM350, MM260 or MM360. The battery is rated for a 3 - 5 year life expectancy. Backed by a 12 month Mighty Mule Warranty and Technical Support.