The Siemens 5SL4404-8CC is a 4-pole miniature circuit breaker from the SENTRON 5SL4 family, rated 4 A with a D tripping characteristic and a 10 kA breaking capacity at 400 V AC. The D curve holds through the magnetizing surge and clears only on a sustained overload or hard short. The 4-pole configuration covers three-phase loads plus the neutral, so it fits a 3P+N distribution board or a three-phase motor circuit where you want the neutral switched. At 4 A it's sized for small motors, control transformers, or lighting sub-circuits drawing under 1 kW at 400 V three-phase.
RoHS compliance is confirmed from June 2013 onward, and REACH candidate-list disclosure is on file. For a panel builder or MRO buyer, that means no substance-restriction surprises in EU or UK jurisdictions. Note the product class B designation — return is restricted, so Siemens expects the order to go through a partner or direct channel rather than open-market returns. That's a logistics flag, not a spec constraint, but it means your procurement contact needs to route the RFQ properly.
Where it sits in the panel
Four-pole width is 4 modules (72 mm), which is the standard footprint for a 4-pole MCB — leaves room for a surge arrestor or RCCB next to it in the same row. Wire termination is the usual screw-clamp for this generation; accepts up to 25 mm² for the incoming and outgoing conductors. At 4 A the thermal dissipation is low enough that you can pack it in a crowded enclosure without derating concerns, as long as ambient stays under 40 °C — standard for most industrial control panels.