As of late the true power of his Echo has been put into question because when put on an adult of the Yamabiko Clan i completely restrains their Echo Kekkei Genkai and they can't hear anything while all it does to Shiro's Echo is restrain it enough for it to be tolerable. Essentially, the Sealing Headphones are the Echo version of a Taijutsu specialists weight. However, instead of being designed for training purposes, although the usage of these headphones is probably helping his Echo grow even further, they were designed to help hold them back.