Seriously, if you want small and variable voltage - I'm going to second the others who have recommended the Varicool from
smoktek.
SmokTek "SmokBox VariCool" - Custom variable volt Box Mod - Efficient switching regulator! adjustable 3,4,5,6.5 volt's & everything between.
I don't have it, but I've been looking at it seriously.
I love that it has switching regulator.
AND
dimensions are (2-3/4" x 1-7/8" x 5/8") - the thing is the size of a business card.
Even the mini lavatubes (of various makes and manufacturers) are usually at least 3.5in long.
Only thing that bothers me about it is the cheap looking plastic case and the internal dial to change the voltage.
I've read a lot of
reviews on it and it doesn't seem to bother other people much.
For the price, I'm thinking it'll be hard to beat for the size and the switching regulator.
(I need very small size too as I keep my PV in my pocket at work. I have a mini lavatube currently and I'm finding it's just a tad too big for comfort.)
