Got the all black model this last Friday. Made the mistake of blowing it indoors as well. My ears rang for about 2 minutes and the dog hid from me from me for the better part of the day. Larger for sure, takes up about 2/3 to 3/5 of an Altoid tin with Very little room to spare above or below it. All in all if you have the space, this is an awesome whistle. I just held it in my mouth and exhaled and got more than an audible chirp that could be heard from a distance, and would carry even further with very little more effort, if you fill your lungs to blow plugs your ears.