I use it in my hero 3 and it runs very well. I am glad I got it. I have hours of footage that took like 32 gigs so it was a nice addition to my bag. I heard hero 3 burn up the 64 gig. I don't know why but they apparently do even if you don't use it and just put it in. This has not burned up or become unreadable so I will update the review if it does mess up.