Yeti SnowMX Ski Outside RunnerDescription YETI SnowMX ski outside runner (aka side blades). Item notes: Note these are singles IE if you're doing both sides you will need to buy qty 2. Inspect Replace notes: You should visually inspect your ski side runners every couple rides or so. Dull edges can be resharpened with a file or grinder. I would suggest they should be replaced once there is less than 1 8" (3mm) or so left of the vertical steel edges exposed from the ski plastic, for