Feature: Simple mechanical structure, it is easy to install. The tire has clear concave and convex surfaces, anti-slip, ensures the better grip and stable operation. Use for educational learning, smart robot car competition, and entertainment. Specification: Axle Outward Diameter: 13.8mm Axle Hole Width: 3.66mm Axle Hole Length: 5.3mm Size: 66mm*26mm(Diameter*Height) Package included: 2 pcs Small Smart Car Wheels.
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