I also have Merrill shoes and boots. There are other labels sewn in on the inside arch of each shoe which does not affect comfort. I found them to be my true size so I would not recommend downsizing or upsizing as some suggest. Overall, it works great. Very much better than in-ear headphones for comfort, and not emitting as constant quiet hiss as some other bluetooth headphones do. Easily installed in 1 mins. Nice sound quality and the battery life is great even for him. I understand these were produced to help protect childrens delicate ears however, they are just a little to soft sounding even at the highest (loudest) setting. I have an eclectic taste in music so was able to test genres from metal, electronica, soul and acoustic, and all sound really nice. I will mention that the soles have fabric on them.