Caution: Minor differences in product design may result in different model numbers. Please check the picture carefully to see if it matches your product. ALL-CARB 5× CXA #4 250-304 Heavy Quick Change Tool Post Boring Bar Holder 13-18. CXA #4 QUICK CHANGE BORING BAR TOOL POST 250-304. For use with CXA tool posts 250-300 or 250-333. Equipped with a split bushing to accommodate a boring bar of smaller diameter. Holds 3/4″ tool with bushing, 1″ diameter without bushing. 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. This product offers the best after-sales service. We are committed to providing you with durable and high quality products. Thank you for choosing our products! Includes: 5 × CXA #4 250-304 Quick Change Tool Post Holder. Quick Change Tool Post. And our office is closed on Sunday and we apologize for the late reply during the holidays. We will do everything we can to give you a satisfying solution. We do our best to resolve any issue. So please talk with us and we will not let you down. FEEDBACK IS VERY IMPORTANT TO US.