SteelSeries RIVAL 600/650 Weights & Weight Box Genuine Product This is a set of weights and a weight box for the SteelSeries gaming mouse "Rival 600" or "Rival 650". You can customize your mouse to your liking by adjusting the weight. The side panel can be removed with magnets to set the weights. Each weight is 4g, and up to 8 weights can be attached. It is also possible to adjust the center of gravity of the mouse.