Group, I use a battery cut off switch 300amps that works fine in three cars. They are great when working on the cars or doing shows with doors open. They are $10.99 + 8.25% tax in Texas + par post. Northern Tool & Equiptment is where I buy them . They come with two keys. If you can't find then then let me know and i will ship you what ever you want. John Hervey, Dherv10@xxxxx