uxcell C7259 Push Button Alligator Clip Test Probe Crocodile Clamp for Multimeter 2 Pcs Body Material: Nickel Plated Brass ; Insulator Material: ABS Max Opening: 6mm/0.24inch Length: 52mm/2.05inch Interface Diameter: 4mm/0.16inch Insulation alligator clip, opening up to 6mm. Can holding all kinds of wire, alligator clip on tooth part is ABS plastic, part of the lower teeth is nickel plated brass conductors, the tail is 4 mm socket, can only be inserted to 4mm banana plug and cannot be welded.