“SEQ” stands for sequential, because the sockets are switched with a time delay to protect against harmful current peaks. All five custom-made US receptacles are equipped with pure, rhodium-coated copper contacts and the DDS filtering, which effectively prevents the backflow of interference signals into other devices when connecting digital devices, as well as interference from the mains. The solid housing made of stainless steel with aluminium and magnesium reliably prevents radio interference. And even a phase tester is not missing.