From Revolution Design Racing Products:
The RDRP Rear Chassis Weight for the Team Associated B64 series of buggies is the ideal tuning option for a range of track conditions. First and foremost it ensures a near perfect chassis balance when standard-size electronics and regular-weight batteries are used while also adding weight for improved rotation into corners and added traction in slippery track conditions. The weight comes machined from high-quality brass, it sports a nice black and golden finish for looks and it weighs in at 28g. Unlike RDRP’s other option parts it isn’t a direct fit as the left chassis side pod needs some DIY, although the work is carried out in under five minutes using a Dremel.