The Siemens SENTRON 5TT5833-2 is an insta contactor with 4 normally-closed (NC) contacts, controlled by a 24 V AC coil. It's rated for 440 V and 25 A, making it suitable for switching resistive and incandescent lamp loads up to 2000 W.
The 4 NC contacts mean this contactor is normally passing current when de-energized — it's the right choice for fail-safe circuits or loads that must stay powered unless the coil is actively pulled in. The 24 V AC coil is standard for building automation and panel control; verify your control transformer matches that voltage type (AC, not DC). Rated 440 V / 25 A on the main poles, with a switching capacity of 2000 W for incandescent lamp loads. That 2000 W figure is the practical limit for a bank of lamps — exceeding it risks contact welding on inrush.
The 71 mm depth and 90 mm height fit inside a standard distribution board or control panel. Supplementary devices can be installed alongside it, so you can add auxiliary contacts or a surge suppressor if needed.