I have one of his "5mw" 405 pens and it came in at 45mw IIRC when I metered it. In a dark room the beam is visible. It likely won't burn unless you cut down the barrel so you can get to the lens to adjust the focus. I think in the other IQS thread someone mentioned how they did it. Overall a nice laser for the 7 or 8 bucks I paid for it.
FWIW I've found that you get a bit more power out of his pens with normal AAAs than NiMHs but I decided to keep using my eneloop rechargeables for the convenience factor. I was using cheap zinc-carbon AAAs that I had sitting around so alkalines may give you better results than I got and make it work it for you.