Hex nut tri spinner. Uses standard 608 bearings and 5/16 nuts. Two models: a 35mm radius and a 30mm radius for smaller hands. This model was designed in Fusion 360. Want to learn how to design your own models? Check out my Fusion 360 Quick Start Course available at https://www.desktopmakes.com/ https://youtu.be/GZ4QvCiovds