The Delmhorst Instrument 315INS-0003 insulation assembly incorporates different pin chucks and retainers to accommodate the larger 4 inch pins, part #608. The 315INS-0003 is a replacement assembly for the 18-ES on to 26-ES without needing to purchase a new 18-ES. This insulation assembly comes with the cable assembly and the 4 inch pins already installed.