Pine Car CoG System Kit from Woodland Scenics. Distribute weight to the best center of gravity (CoG) location and optimize your car's performance and stability. Screw-in, adjustable Tungsten CoG Weights make it possible to distribute weight quickly and easily. Test your racer’s speed and fine-tune CoG weight placement with the included adjustment tool. Includes 3/8" drill bit. The CoG System is designed to fine-tune a car’s center of gravity (1/2" to 1" forward of rear axle) and is not intended to overcome extreme weight distribution. Patent Pending.