This is the Ultimate Racing Lightweight  Wheel Hexagon Set.

They are machined from T6-7075 Aluminum and anodized in dark gray. Intended for Mugen, Associated, Xray, Sworkz, Losi and Tekno among others.

Thanks to its design, its weight has been lightened about 25% compared to the original Mugen ones.

All the apexes of the hexagon have a chamfer that helps to make wheel changes faster and easier.