Cal Test Electronics CT4448 Insulated BNC to 4mm Banana Jack Attenuators are rated to 1000V CAT II/600V CAT III and are ideal or lower frequency (<100kHz) but higher voltage applications where safety calls for more robust probes and leads than standard oscilloscope probes. Using 4mm DMM probes and/or insulated alligator clips provides a safer, more durable handheld test setup. The CT4448 devices are available in 10x, 20x, and 100x attenuation options with 1MΩ impedance and accept 4mm sheathed banana plugs allowing for work in higher voltages and CAT environments such as electrical panel mains.