If you're looking for a great little lock box for your vehicle in those moments when you can't carry your firearm, check out the LifePod from Vaultek. I bought two of the Colion Noir models which come with the steel tether cable that I have looped through the tie down mounts in my M550i's trunk. Pictured here is my Kimber Ultra CDP LG (3" barrel) and my Kimber Pro CDP II (4" barrel) - both with room for two spare mags.
BTW, you can use it with the supplied keys, or use a 4-8 digit code - or both. You can also disable the key lock from the inside so it can't be jimmied. It's powered with a 9-volt battery, but if it's dead there is a micro-USB port on the front to provide power to unlock it. It is also completely sealed and is water-resistant.
I am VERY pleased with my purchase. Check it out!
Vaultek LifePod:
https://vaulteksafe.com/product/vaultek-safes/lifepod/