I have an Arc AAA on my keyring and a Mag 2 AAA in my other pocket. The Mag is cheap enough to hand over is someone wants to borrow my light plus it used the same AAA cells as the Arc AAA. Also since its a incandescent light I can use it until the batteries run down and the light gets dim then feed them to the Arc AAA which can keep working for a lot longer. I carry a Wave on my belt and the backup for it is a Gerber ridge knive with stud and clip removed so it is thin enough to fit in my key case with the Arc and my keys. Since I need my keys to leave the house and or drive anywhere I will always have the Arc and gerber blade with me both stealthaly hidden in the leather key case making my mini psk.