These are the OpenRC car shocks for 1:10 RC car.I have replaced all my original shocks and will continue develop these. Consider it a proof of concept and experimental though.Hardness of the spring can be adjusted by adding/removing "rings" or change the shape of them. Spring needs to be printed in Nylon to work!1 pcs 50mm M3 screw needed and two smaller ones to keep the "lid" in place.Print and remove support. Check the pictures when assemblying..Check out the video for a short demo: http://youtu.be/oeTo3QebAZM