These YHDC mini current transformers can measure current up to 80A, and fit around wires that are up to 10mm in diameter. They are only 2.3 x 2.6 x 4cm. and have custom 3.5mm jacks which plug directly into our power meters. A TVS diode is built in for safety, and to prevent open circuiting. The output is 26.6mA, when the current is 80A.