OfficinaRC tungsten copper M3 screws
OfficinaRC’s new series of tungsten copper screws are designed for those looking to bring the weight distribution and centre of gravity of their car to the next level. These countersunk head screws come in three sizes, 3x5mm, 3x6mm and 3x8mm, and enable you to add a large amount of weight at any point in the car in the lowest possible point under the chassis. Sold in packs of 4, due to the nature of the material they require care not to damage the head when fastening them.
Source: OfficinaRC [officinarc.com]