Couldn't Be Easier
I had a drawer FULL of half used batteries from mics used for some community theatre and didn't know how much was left in them. I hate to throw useful things away, so I picked this up. It works perfectly! Very simple, easy to read, no frills, just a pretty accurate battery tester. If you've got a crap load of batteries and you have NO IDEA how much juice is left pick this up. Heck, grab this with another order and get free shipping, it's a great filler item.

Finally
This is a great little tool. I had another brand like this one, and wore it out. Nearly every other replacement requires a battery, but not this one. It is compact, works easily and quickly, and as I am old enough to have grown up with analog gauges and dials, I can read it just fine. I am a little worried about the spring that closes the jaw of the tool, but the meter will still function even if it does die, so I'm not too worried.

Uncomplicated
Terribly uncomplicated, compact design, no bells and whistles, does just what you need it to do, without requiring its own power source. You can carry it in a camera case.

Cheap and so so good
Awkard to use, doesn't ever show full charged batteries, which may be my batteries because that's the reason I bought it, was to test out a batch of them I bought from ebay, that didn't work in my camera.

it works
this is a basic little battery tester, but it isn't very accurate. Some batteries read "okay" but really need a fresh charge. I would not recommend this product if you depend on accurate charge readings.