MOC Universal Wheel 92911 bb607 Stainles Steel Ball Compatible with Robot EV3 6023956 4610380 99948 Building Blocks Technical Parts Power Functions Pack of 4PCS

This was as described. Quality product. Functions just as it should. The value comparative to name brand is excellent. It is compatible with Spike Prime, with one caveat. You cannot remove the metal castor ball to replace the plastic Spike Prime ball. This is a different size ball and is smaller than the plastic one. So unfortunately this did not suit my purposes. I wanted to use the Spike Prime turquoise castor piece and replace the plastic ball with this metal ball. That cannot be done. Still 5 stars because my thoughts of using it as replacement parts were not the products intended purpose.

For the EV3 LEGO system this is an often needed replacement. The steal gets rough impacting performance. This is a great replacement and will give you spares.