Mighty Mule Volt Replacement Battery for GTO Mighty Mule Automatic Gate Openers AMP hour replacement battery. Compatible with Mighty Mule gate openers fm, fm, fm, fm, mm slb and mm slb only. THD SKU .Mighty Mule proudly announces the newest additions to the Mighty Mule Automatic Gate Opener range with the launch of the MMDIAS Single Gate Opener and MMDIAD Dual Gate Opener ..Ramset manufactures the most reliable automatic gate opener. for automatic gate openers that are easy to install and operate..The Patriot solar swing gate opener for your home, farm or ranch. Made in the USA!.