AK 2 B 2540 I CAT II Crocodile Clips. Hirschmann Test and Measurement AK 2 B 2540 I contact protected crocodile clip, features high strength insulation a 4mm unsprung socket and nickel plated brass jaws. These contact protected crocodile clips have a clamping range of up to 30mm in diameter, suitable for use with 4mm safety protected measuring leads. Rated voltage 1000 VAC/DC Rated current 32A CAT II Contact resistance 10 m Unspring 4mm socket