Product Overview The MT048-K takes the four-stage copper isolator and adds a lock cylinder: the dial can no longer be turned by anyone who does not hold the key. That single change turns a convenient dual-battery switch into a controlled access point — useful wherever an unattended boat, stored camper or shared machine must stay electrically dead. The electrical platform is unchanged. Copper conductors carry a 250A continuous load with a 360A intermittent allowance up to a