This versatile system includes the electronic timer, one dual-purpose gate, a 9VDC power supply, and a detailed instructor’s manual. The electronic box for the system has two standard 1/4″ phono jacks for double gate operation in the GATE and PULSE modes. Features include:• Dual purpose gate - allows internal or external measurements• Universal clamps - allow the gate to be easily positioned in any angle• Electronic control box - permits stand alone operation without a computerFour timing modes are possible:• Gate - measures the time of an interruption.• Pulse - measures time between interruptions.• Pendulum - measures the time between the first and third interruption.• Manual - allows you to use the timing system as a stopwatch.