Made out of aircraft aluminum protected by red anodized plating * Self adjusting with no additional support needed from .001" to 1.2" tall * Low profile for maximum tool holder clearance * Swivel cam action allows straight down clamping force with multiple positions on a sub plate * Based on 5/16-18, M8 Part# SPT-013, other sizes 1/4-20, M6 bolts Part# SPT-012