ROBERT S roughly 2.5" long. I bought it as a dive whistle. I wanted something easy to grab.

MARK T If you were to put 1.5 regular basketball or soccer referee whistles together, then you get the picture in both length and width. To be precise I measured it and it is 3 inches long and a little less than an inch thick. However, I have owned them for almost 3 years and you WILL NOT be disappointed. I would give one to every child and woman in my life as a safety precaution because it gets attention when blown at even half-force. I recently went looking for my kids and wife at the local carnival and there was no way I was going to find them, so I blew the STORM and they came to me and everyone else just looked at me...LOL.

MICHAEL O About 3" long by about 2" at the widest by about 1" thick. Probably the largest whistle I have seen and by far the loudest. We own 4 in the family. I suppose you have to judge for yourself what is most important - size or sound.

SCOTT R It's big, about 50% bigger than a normal full size whistle ... but ... you are buying this for an emergency situation right? ... so 50% bigger for the Undisputed loudest "lung powered" whistle is worth it.

DAW E Thank you. Do you know what the range of hearing would be? How do you think it would compare to this? SOL Rescue Howler Whistle (2 pack) SKU: ADKRHW

BARRY A This whistle is between 3.5 and 4 inches from end to end. In an emergency, this makes it easy to find and handle, as does the bright orange color. I bought this for my inflatable boat and I must say, this whistle is really, really loud!

EDWARD K We bought these whistles for our Emergency Bug Out Bags so size was a concern. These are somewhat bulky due to their shape but the volume of the whistle more than makes up for the size. I would not hesitate to recommend one for your personal use even for such activities as running, biking, hiking.

KYUNG IL M about 4 inches long.