Pololu-1090-Wheels-42-x-19mm-Pair-Pololu-1090-p-A-set-of-white-plastic-wheels-with-rubber-tyres-The-wheels-will-press-fit-onto-the-3mm-D-shafts-on-motors-Teeth-on-the-hub-optionally-allow-a-reflectance-sensor-to-be-used-for-encoder-feedback-br-br-These-brackets-are-just-one-of-the-many-b-Pololu-b-accessories-carried-by-b-Rapid-b-p-Pololu-1090-Wheels-42x19mm-Pair-