I used this battery switch on my candle lamp project (just a few prints and a led, not really a "project"...), and it was the perfect fit for this one! It is as compact as it gets and amazingly convenient.
Really a great simple model! Overworked did a great job!
15 precent, doesn't really matters.
Using my printer (which is not fully calibrated yet) the hole was a little too small, so I used a knife to make it abit bigger, then it was flawless.
On is up, Off is to the side.