So unless you do some magic, the top of the mouth flies up and the whole thing looks stupid. You need to find a way to anchor the top of the mouth somewhere the helmet using a clip, velcro, or whatever else you can think of. It's good for slow rides but pretty useless at anything higher than 40 MPH.
I love kids' reactions at red lights. Gotta wave back at the kids. Make them think that all Sesame Street and Muppet characters are secretly riding bikes under the table.