Riedell PowerDyne Arius Derby Plates - Red (Pair)The patented design of the Arius plate from PowerDyne works great for all skating disciplines as it provides more power, stability, control and manoeuvrability than old fashioned kingpin designs. PowerDyne have completely re invented the traditional roller skate truck there is no kingpin, and it will feel like nothing you've ever skated. Feedback from skaters of all disciplines has been overwhelmingly positive. Manchester Roller Derby and Team England