Fluke ITP120 Optically Isolated External Trigger ProbeDesigned for use with Fluke ScopeMeter 123. The probe connects to the optical port of the ScopeMeter 123, and features isolated external triggering, for measurements that require external triggering or triggering on floating reference signals. Probe length is 1. 2m (48 inch). The probe includes a hookclip with ground lead, and a 9 Volt Alkaline battery. Input impedance is 10MO in parallel with 15pF. Trigger level: TTL compatible (High = 2V, Low = 0.