These wheels are made of a perfect material for fingerboarding on all terrains. They squeak on smooth surfaces and grip rough surfaces perfectly. That being said... the bearings do not free spin very well, and one out of the four bearings came rattling-- hardly spinning at all. I had planned to use these on my indoor setup, but instead, I'm going to shred them to bits on street because of this. I hope the sets others will receive have better quality control & assurance. I love the intended design, shape, material, and most of all: performance. For the price, you will very seldom get something this solid.
