Elenco Electronics LP-560 Logic Probe Logic probe provides convenient and precise measurement of Logic circuits Displays Logic levels (high or low), pulses and Voltage transients down to 25 nanoseconds Tests all Logic families (ttl, lsi, CMOS, ect) Captures pulses to 25ns(20mhz), Plus more features For nearly 50 years elenco has been producing reliable as well as affordable electronic test equipment, tools, and Educational kits