Carmex External Multiple Threading Insert holder - For Carbide External/Internal Threading Inserts - SLE0045E21-4The Carmex External Internal Threading Insert Holder (SLE0045E21 4) is a precision Mill Thread tool holder designed for CNC milling centers that need fast, repeatable threading with carbide inserts. It supports both external and internal threading tasks, delivering flexible performance in a single, robust solution. Multi insert capacity: holds 34 carbide inserts per holder to increase productivity and allow larger thread forms per pass. External and