I purchased these as backups. For my drone. I broke a blade the other day for the first time in one five years of ownership. I wanted a few backups just in case the price seemed right, but after reading the comments, i will always do a preflight to check for lose rivets or possibly just hit. The rivets dead center on an anvil with a pointy center punch to make sure they are properly expanded in their sockets i’m happy with these replacement propellers, they don’t look exactly like the the mavic ones, but close eo replacement blades for an expensive drone got the job Done great product Music buy these way cheaper and not very loud at all.