Carmex Internal Multiple Threading Insert holder - For Carbide External/Internal Threading Inserts - SR0100E40-4The Carmex Internal Multiple Threading Insert Holder SR0100E40 4 is a precision mill thread tool holder designed for internal threading with carbide inserts. Built for CNC milling environments, it enables fast, multi insert threading with dependable stability. Insert capacity: Holds 48 carbide threading inserts per holder for efficient, multi tooth cutting. Compatibility: Part of Carmex's Mill Thread line and designed for internal applications only.