Apple routers come in two flavours, the AirPort Extreme and the Airport Express. There is also a variant of the Extreme called the Time Capsule, which has a built-in HDD of 2 or 3 Tb capacity. AirPorts are simple looking devices, with only one light on the front, which glows a steady green when all is well, and turns amber when attention is required. They are set up using AirPort Utility, which is supplied with Mac computers and can be downloaded for iOS devices and Windows PC. Various connections may be made to the routers. Most are the same, but there are a couple of differences so you need to check your requirements (or buy both). The Extreme has one Ethernet input, for connection to a cable modem or the like. It also has 3 Ethernet outputs for hard connection to computer and network equipment. The Express has only one of each connection. Both routers have a USB port, for connection to a network printer. That of the Extreme will also operate a network HDD. The Express also has a 3.5mm audio output, which doubles as an digital optical interface. Equipment connected to this output can be used via AirPlay. Both routers can handle wireless clients and can control a network or extend it.