What kind of power must cyclocrossers generate to derive any advantage using aero deep dish wheels when they are up to their bb’s in mud & sawdust?
The 303 rim was designed specifically for the Spring Classics and for Cyclocross. Lightweight (1206 grams), aerodynamic (faster than most deeper V section rims), 45mm depth helps with mud (and sand) shedding, has a rounded radius on the outside diameter of the rim that helps prevent pinch flatting when the rim bottoms out on a rock or root, reinforced with a Kevlar stitching under the outside diameter for greater impact resistance, outside diameter that is designed for gluing 27mm-32mm tires (using laser scans of actual tires), the wheel is very comfortable yet laterally very stiff, 88/188 hubsets with labyrinth seals to keep out mud, sand, water.
And aero is aero at any speed. (that last bit was me).