Check out this pricey little guy. It shouldn’t be a surprise the Surefire is premium build and price but long lasting, their new Sidekick offers some serious punch in a little case. A small (car fob) size package holds a USB rechargeable 5-300 LM in 2 oz. Pretty small and decent run time (1.25 to 4hrs) the USB recharge makes all the difference since you will likely be recharging it often, at $79 its a big price for a little guy. deets here.