All collet chucks are balanced to 12,000 rpm. ER collet chucks to DIN 6499 standard with high precision AT3 taper. DIN 69871 and ISO are ideal for high performance drilling using solid carbide tooling. ER collet chucks can also be used for milling, tapping and mounting most straight shank tools. Adaptors are supplied with standard locknut and through coolant stop screws.