Smooth - Smooth wheels come with a shiny coating on the riding surface that feels grippy at first, but wears away quickly.
Wheel Profile
Wide - More traction and stability at high speed so you'll be less likely to slip out of your line.
Wheel Shape
Double Duros - Double Duros have a 99a outer durometer wrapped around a 95a inner durometer. This duo combines the best of both worlds by providing fast and loud slides and a smooth roll on the roughest surfaces.
Hardline - Hardline wheels come in a conical shape with sharp edges and an extra wide riding surface for maximum grip and control on any terrain.
Durometer
101a - Most common durometer offering a good balance between speed and grip. Meant for skateparks and other smooth surfaces.
95a - Great for beginners until they gain control needed for harder durometers. Also useful in your neighbor's beat up pool and gnarly ditches.