Don’t know, never flown with them 
I fitted two of them to the rear arms and folded the arms in.
@Peter posted a pic of the low noise props touching the bottom of the Mavic. The problem I have is my moulded case, I literally don’t have the clearance for the Mavic to drop cleanly in to the laser-cut foam insert 
I know it’s only about 3mm on each side, but my case is just that tight as it is. I can force it in, but I’m not going to do that.
So alas, I’m selling them before I’ve even flown with them 
£20 delivered, that’s even cheaper than Heliguy 