What it is and where it fits
The ABB 1SDA066988R1 is an Ekip TT trip unit designed for the XT2 and XT4 molded-case circuit breaker frames. It is the electronic trip module that plugs into the breaker, providing adjustable protection curves and communication capability. The part is listed under Electrical Test Equipment / High Voltage Testers, reflecting its role in testing and measurement within switchgear.