4-Port Switch -- cheapest way to fan a single uplink out to multiple client devices. Purely a Layer-2 extension: it has no DHCP smarts of its own and doesn't participate in IP assignment.
No DHCP smarts of its own; just extends a segment -- every device plugged into it still gets its address from whatever router's DHCP server is upstream, the switch itself is invisible to that negotiation.
5W typical draw, cheapest device in the roster to power -- the constraint here is port count, never wattage.
Fine for a handful of client devices before you need a second switch (or the 8-port model) -- once you're regularly running out of ports, that's the signal to upgrade rather than daisy-chaining more 4-ports than necessary.
Tip: because it adds zero DHCP or firewall logic of its own, wiring problems downstream of a switch are almost always actually a router/firewall/IP problem, not a switch problem -- don't waste diagnostic time on the switch itself.
Takes the Redundant PSU upgrade ($1800, Inspector → Upgrades): it adds a second power input, PSU2. Wire PSU2 to a DIFFERENT PDU or UPS than PSU1 and this device keeps running when either one dies. Two feeds from the SAME PDU protects nothing -- the redundancy panel simulates that PDU failing and watches the device fail with it regardless of cable count. The spare idles at zero draw, so it costs nothing extra on the power bill. See Redundancy & Failover.