81PLUS-UT01 Single pole sockThe socket 81PLUS-UT01 from E-T-A is designed to accommodate circuit breakers series 2216-S or REF16-S. The electrical connection is made quickly and easily via screw terminals. The socket 81PLUS UT01 is installed on TS35 DIN rail.et for circuit breakers 2216-S or REF16-S.