I bought one last year and have been "trying" to use this effectively. It is about the size of a coachs whistle.
I do like it for it's compact size but, to me anyway, does not have the same sound as other larger grunt tubes, at leasst for the lower pitched buck grunts. It may be dead on for fawn bleats and such, but I really have not used anything else up to this point to compare. I am thinking of getting the Primos hardwood grunter, but just don't know if I am buying foolishly. Anyone have any idea or input on this please throw it out there.