7MH-9 INS US Rubber Insert for #90 Capping Chuck. For use with air-operated or electric tighteners and Interchangeable hand gripper. The manual hand gripper attaches to our capping chucks to tighten cans, bottles, and jars quickly and easily. Order Chucks and Inserts separately. for cap sizes 3-1/8" to 3-15/16" (80-100 mm).