Natural Rocker (NR) frames use four larger wheels on a three-position rocker, to allow preservation of speed (better glide) and enhanced shock absorption (smoother roll) compared to smaller wheels. The Natural Rocker frames is available in three different sizes, the NR90, the NR100, and the NR110 to best fit your skating style or boot size. Recommended frame length based on boot size: For boot size 7.5US and smaller, we recommend the NR90. The NR90 is the most maneuverable of the Natural Rocker Wizard Frames and is great for anyone looking to get into the Wizard skating style.For size 7.5-10.5US, we recommend the NR100. The NR100 is the most versatile of the NR Frames and provides great stability and maneuverability.Skaters with size 10.5US boots or larger are recommended to use the NR110. The NR110 offers the best efficiency and speed of the Wizard line of frames but is less maneuverable, so it is not recommended for new skaters. All sizes of NR Frames are compatible with all sizes of UFS boots. Details: NR90: Natural Rocker GeometryDesigned for 4 x 90mm wheels91mm effective contact (underfoot)273mm wheel base NR100: Natural Rocker GeometryDesigned for 4 x 100mm wheels101mm effective contact (underfoot)303mm wheel base NR110: Natural Rocker GeometryDesigned for 4 x 110mm wheels111mm effective contact (underfoot)333mm wheel base Complete Frame Option Includes:- A Pair of Wizard NR Frames- 8 Wizard Natural Rocker Wheels 86a- 16 Sonic Swiss Bearings- 8 bearing spacers Wizard frames are designed specifically for UFS-style boots (flat base) to offer the lowest ride height, and optimal control of larger wheels and longer frames.