The Heavy Ranger Mobile Universal Trailer Tester (MUTT®) is a commercial trailer light and electric brakes tester that reduces guesswork and saves time by powering each trailer electrical circuit in 7-way round pin arrangements. This allows for proper verification of wiring configuration, ground integrity, short circuit and overload conditions, along with electric brake operation and turn signal simulation. The Heavy Ranger MUTT® features a water resistant, rugged design and features an internal battery compartment and external 12v power port which can be used as a memory saver, test light supply or trickle charge input.; Features and Benefits: Test 7-way round pin trailer side harnesses; Short circuit protection; Turn signal simulation and power verification LED; Water resistant; Internal battery compartment (battery not included); ncludes: 500 mA Battery Charger (#CHR0001)