The Airport Express grew another Ethernet port.

Apple’s little-brother base station got a makeover. It’s now the same size as an Apple TV, with a regular power cable that makes it easier to locate in more places. (The old versions had a fold-out plug, unless you used an optional extension cord kit.) It also grew a new Ethernet port, now with separate WAN and LAN ports. But the changes inside are even better.

802.11n speeds came to the AirPort Express in 2008, but in single-band mode. Now the Express can use the 2.4GHz band (for all of your 802.11g and earlier devices, as well as iPhones and pre-2006 Macs), and the 5GHz band (for your new Macs, all iPads, and other 5GHz-compatible devices), without having to restart the router to switch between them. When needed, your 5GHz-friendly devices can even jump down to 2.4GHz, which has slower throughput but longer range.

It’s super simple to set up as either a base station or a bridge. You just hook it up and fire up AirPort Utility, on the Mac or now on an iOS device. The default option is to create a new network, but if you click More Options you can also use it as a bridge to extend your existing network, or you can tell AirPort Utility that you’re replacing an existing AirPort router with this one, and it’ll transfer the settings to this new AirPort Express for a seamless transition.

The form factor matches the Apple TV.

When setting it up as a new network, you can enable Guest Mode, which creates a separate Wi-Fi network (with or without a password) for your guests, so you don’t have to share your password. Plus, the guests only have internet access; they can’t use your printers or access the other machines on your network. A built-in firewall and lots of encryption choices round out the key security features.

For music, you can connect a set of powered speakers using a digital optical cable, a mini-stereo-to-RCA cable, or a mini-stereo-to-mini-stereo cable. Then just use AirPort Utility to enable AirPlay on the Express, and the speakers show up in iTunes (and on iOS devices and Apple TVs) as AirPlay speakers you can stream audio to.

The bottom line. It’s not quite as powerful as the Time Capsule ($299 and $499, www.apple.com) or AirPort Extreme ($179), which can pump out three data streams to the Express’s two, and those two base stations also let you connect a USB hard drive, while the Express’s USB port is just for a printer. The Express is stuck with 10/100Base-T Ethernet speeds (no limit on Wi-Fi speeds) instead of Gigabit Ethernet. But the AirPort Express is still a capable, full-featured router for a decent price.