M12 open-end metal washer (Cybercart service part).
Premium components
Club Booster V2's body is made of aircraft grade extruded aluminum — making Club Booster V2 impressively durable, long-lasting and strong.
Each wheel is constructed from wear resistant polyurethane, letting them roll over virtually anything without worry or damage. Rocks, sand, asphalt and more, Club Booster V2 will tread over any terrain without complaint or trouble.