For Serpent 747, purpose made brass slide- weights which can be mounted into the slots pre-made in the 747 chassis.
These weigh 25 grams each and maximum 3 can be fitted. Black coated, laser engraved, and comes with correct screw.
The chassis has 3 slots for the slide-weights, which slide in position and are secured with a screw. The chassis and set-up sheet shows lines to indicate and record the positions.
Its very easy and fast to change and has a lot of influence in the cars balance and handling .