Bought this to cover the endpin on a cello, obviously. Mainly it is used to protect the surroundings when carrying the instrument. To clarify, I have a padded gig bag instead of a hard case, and the endpin sticks out a bit.
The cap fits nicely and for the price it is simply a great piece. Evidently doesn't fall off or break too easily. Easy to remove and put back on.
I wouldn't exactly call it a "floor protector" since the cap is too small and stiff to hold the cello in place when playing, at least on a wooden floor.
For simply covering the sharp endpin, there's really nothing to blame or praise this item for. Good enough quality to resist cold, occasional bumps and other hazards when lugging the instrument around.
For similar purposes I could recommend this item.