The weight reducing pulley group adopts a silent ball bearing design, which rotates smoothly and can rotate with minimal force. It is quiet, durable, and not easily damaged. Through the combination of two weight reduction pulleys and the use of weight reduction high permeability elastic lines and appropriate weights for weight balancing, the weight reduction is more stable and can effectively offset the weight of cables and mouse head mounted devices, minimizing the impact of external factors on the free movement of mice.