1U KVM Console -- console-over-IP for up to 4 devices. Gives real terminal access to whatever's wired to it without needing a dedicated Terminal Server device racked as well.
Real terminal diagnostics (help/ip/devices/ping/who/netstat/logs/man and more) on anything wired to it -- the same command set a Terminal Server exposes, just reachable through this device's console ports instead.
5W typical draw, 50W max -- one of the cheapest devices in the roster to power, which matters little on its own but adds up when you're deciding what to rack in a tight, low-capacity satellite setup.
No need to own a dedicated Terminal Server just to get a shell on a device -- useful early game, or anywhere you want diagnostics without spending a rack slot and a PDU outlet on a Terminal Server that would otherwise sit idle.
Tip: the 4-device limit is per console, not per rack -- a rack with more than 4 devices you want shell access to still needs either a second KVM or an actual Terminal Server to cover the rest.