This thing is nowhere near the 40 grams claimed in the tech specs over there. I put it on my digital kitchen scale and it weighed in at 7 grams, with the little lanyard included. Light enough that you (quite literally) won't even notice you're carrying it. Oh, and it's loud and small, and the lack of a pea makes it so it won't rattle around in/on your pack. well worth 2.50.