The Global Specialties 4001 0.5 to 5 MHz Pulse Generator is uniquely designed to permit precise tailoring of pulse repetition rates and duty cycles over a wide range through the independent setting of pulse width and pulse spacing. Both pulse width and pulse spacing are continuously variable over seven decade ranges from 100 ns to 1 s, with outputs from 0.5 Hz to 5 MHz. Its uncomplicated, with a rugged design and high quality components to help ensure long and dependable service. Notable features include two simultaneous independent outputs (TTL and variable) with rise and fall times less than 30 nsec, 20 nsec TTL compatible leading-edge sync pulse output, and independent pulse width and pulse spacing controls (both selectable from 100 nsec to 1 sec). Four front panel push-button selectable operating modes with one-shot push-button can be used to produce pulse trains or enable a single output pulse. Pulse duration is determined by width control. All of these features, plus an uncomplicated front panel layout all add up to an effective solution to a wide range of pulse source problems. The 4001 pulse generator with its many features and ease of operation make it a welcome addition to any lab. Some of the varied uses for the 4001 are as a detector for missing pulses, tracing digital logic flow, analyzing microprocessor programs, or testing radio control receivers. The 4001 can also be used in audio testing and for many other applications requiring a precision pulse source.