Machined in house from Delrin 500 Acetal base stock - these Stage 3 bushings are a 70d durometer hardness (a different scale than the a scale of our urethane bushings). This gives you the stiffness of a solid aluminum mount without some of the harshness (keep in mind these will cause much more vibration than even our stage 2 bushings).
Priced as a pair - enough to replace the bushings on 1 Gen 2 BFI engine mount.