This is a true technician's isolation transformer that does not carry the ground or the neutral through from the source. This is a crucial difference from most other isolation transformers on the market. It's a joy to have the flexibility to safely establish an arbitrary local ground reference anywhere in an active circuit for *one* oscilloscope probe (note that additional probes must use that same ground reference point to avoid the risk of a short circuit and personal injury or damage to the oscilloscope or the UUT). This product uses a toroidal transformer that is quiet, efficient and powerful. I'm pleased with the isolation transformer, the customer service and the shipping department who expertly and carefully packaged this heavy unit to prevent damage in transit.