Air Bumps are worth their weight in Gold, but not all of us can afford Gold. So here is a cheap alternative. Designed as a direct substitute for Air Bumps. Allows you to simply bolt in Air Bumps when you’re ready with “ZERO” additional Fab from you. Spacer made from Solid 6061 T6 Aluminum With 2″ Poly Bump Cone .750″ hardware for mounting to can.