No surprises, they are pretty much what you would expect. Made out of hard rubber or plastic. There are six to the pack, which is nice in case you lose one or break it. They go on very easily. A bit trickier to remove but certainly not difficult. I haven't flown with them yet -- it was too late by time I got home.

I doubt it will be an issue but the squeeze tabs used to attach and remove them will be spinning at high speed at the center of the propeller so it'll be one more thing to be careful about when it comes to safety. I suppose it's possible that these tabs, if damaged, could cause some imbalance or maybe airflow issues, though I'm sure DJI tested them under various conditions.

The good news is that I don't believe any propellers will be falling off when these locks are properly attached.

Another nice thing about these locks is they only go on with the propeller fully screwed onto the motor. I believe some people may have had an issue with propellers falsely appearing to be screwed on all the way. These locks will ensure that mistake can't be made.

Good to hear.  I got a tracking number for mine today.

Got mine today, easy to install, looking forward to a flight this weekend

Still awaiting on B&H to send my locks !