Active Differential oscilloscope Probe, Model ADP311 is the product manufactured by Aplab Limited. The company Aplab Limited is an ISO 9001-2000 certified one. The product Active Differential Probe is an active differential oscilloscope probe. The differential techniques employed in the Active Differential oscilloscope Probe permits measurement to be taken from two points in a circuit without reference to the ground. This allows Active Differential oscilloscope Probe to be safely grounded without the use of opto Isolators or Isolating transformers.