The TeSys LA9FL4K4F is a mechanical interlock accessory from the TeSys F range, designed to physically prevent simultaneous closure of three vertically mounted contactors. It interlocks bottom-position LC1F115 through LC1F150 3P or 4P units, middle-position LC1F500 2P/3P/4P units, and top-position LC1F630 3P/4P or LC1F800 3P units, plus the corresponding CR1F reversing contactors.
Mounting position is 3 vertical, meaning it occupies the space between three contactors stacked in a vertical column on a DIN rail or backplate. The mechanical interlock clips between the contactor faces — no additional wiring, just a positive mechanical tie that guarantees only one contactor can close at a time.