The TeSys LX4D4SW is a replacement control relay-contactor, listed under Category 18401-WORLD SERVICE PARTS(CTR ACCESS). The description flags this as an Obs _Repl cntrl rly-contactor w/ TeSys — a replacement for an earlier control relay or contactor within the same family. If you have a legacy TeSys contactor or relay that's no longer listed, this is the drop-in intended to take its place on the DIN rail. Because it's a world service part, it's stocked for global support of installed bases. You're not chasing a discontinued orphan; this is the current-service variant meant to keep existing panels running without a redesign.
The description flags it as an Obs _Repl, superseding an earlier part number. Confirm coil voltage and contact configuration match your existing wiring before installation.
Integration Note
It's sized for panel integration where space is already allocated for a contactor footprint.