Every one that ahs given this a bad review are just fanboys of other companies. this fan is AMAZING! it gets rid of fog compleley and its not as loud as others have said. i dont fidn that it decreases ur hearing at all.
Im telling you this is a great fan for your mask....i use a proteus and i NEVER fog up anymore....i promise u NEVER......anyone that says diffenrnt hasnt used it or is a fanboy coming form another company.
Defe\inatly worth the money! helps EXTREMELY. you WILL NOT be disapointed.