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Continue to ChatPiston and Ring Set - 47cc, 49cc, 44mm, 10 mm, 1 window (7pcs) - 30P8421 - PBC1813F1 - https://www.electricbikeusa.net/shop/engines-parts-upgrades/piston-and-ring-set-47cc-49cc-44mm-10-mm-1-window-7pcs-30p8421-pbc1813f1