Securely holds 1/2" - 3/4" square tool bits For use with CXA tool posts 250-300 or 250-333. Interchangeable with Dorian, Aloris, & Phase II CXA series tool posts. While we guarantee your satisfaction, these especially work best with our matching tool posts Precision ground and hardened. Completely sealed for maintenance free operation Turning and facing tools can be locked together (saving time and labor when changing operations). 4Pcs New CXA #1 Quick Change 250-301 Tool Post Turning & Facing Holder. We will do everything we can to give you a satisfying solution. We do our best ...