This is a mini split base current transformer; it's the smallest one compared to the similar products (output 100MA). The diameter of inner hole is 16mm, the accuracy is less than equal 0.5 grade, Our ac sensing relay using snap joint structure, it can be fixed to the cable directly through nylon ties. The amp transformer is with Built-in input coil; small and light, easy to install. Fully enclosed CT, good mechanical properties and environmental resistance, strong voltage isolation capability, safety and reliability. Material: ABS colour: black Package Contents: 3 x Current Transformer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.