The Siemens 5TT5001-0 is a SENTRON Insta contactor — a compact switching device for lighting, resistive, and small motor loads in commercial or residential panels. It carries one normally-open and one normally-closed contact, both rated for 230 V AC coil voltage, with the main contacts handling 400 V 20 A as noted in the description.
The 230 V AC coil is the only operating voltage listed — no dual-range or wide-tolerance coil here, so verify your control voltage matches exactly. The 1 NO + 1 NC contact arrangement is common for interlocking or auxiliary switching; the NO side makes on coil pickup, the NC side breaks.
Snap-on DIN rail mount, 17.5 mm wide, 71 mm depth (64 mm installation depth behind the rail). The design accepts supplementary devices (add-on auxiliary contact blocks or timers) per the product extension note, so you can stack functionality without replacing the base unit.