Moeller Battery Disconnect Switch with Key

Can you purchase additional "keys" in case you lose the only one that comes with the unit?

when you insert the key and turn it, the Battery is now connected, or vise versa?

I'm looking for a disconnect switch with 5/16 threads, not 3/8 or 10mm - What size does this one have?

1 cable from + to a s/o post, another cable back to + from other post.Where do the cables of what you wish to supply power to attach, battery or post?