Cal Test Electronics CT3021 Large Alligator Clips are fully insulated large alligator clips with 4mm sheathed banana jacks. These alligator clips operate up to 5kV when used in non-category environments up to 2kV. The CT3021 alligator clips are only compatible with CT3018 and CT3020 long-reach high-voltage test leads. The alligator clips are 1000V CAT IV rated, open to 24mm, and accommodate terminals up to ø16mm (diameter).