How many of you use one. I put one on every machine that i own,that has a battery that is. reason being on the farm back in the 70's i went to start ....ih 544 and the shut off cable crossed the starter leades and oil fillter,when it started i had an oil fire and could not shut tractor down,burnt through shut off cable. well i grabed the lever on the fuel injecter pump to shut down,a good jolt there! put out fire all is well. the other instance was my part time const. job after work out side shop having a few beers we hear a loader in shop turning over but not starting,suspect somone is forgeting to hit the throtle pedel you had to pull back by hand to stop engine. we looked in shop nobody there the loader had wires make contact wile parked good thing a guy knew were the bolt cutters were and cut battery cable. So for $25.00 for master disconect i installed one on 4 wheelers,and every tractor i had. Cat has master on every piece,and jd const. equipment has started to. easy to install,you put inline on ground side of batt. park tractor and turn shitch off. P.S most storage places make you disconect batt. on anything you put in thier bld. just for fire reasons.