Time Capsule is a wireless network-attached storage device combined with a wireless residential gateway router made by Apple.
Time Capsule is described as a "Backup Appliance", designed to work in tandem with the Time Machine backup utility, introduced in Mac OS X 10.5 "Leopard."
The device includes a full AirPort Extreme Base Station with 802.11n wireless, an Ethernet WAN port, three Ethernet LAN ports, and one USB port. There is also an internal "Server grade" hard drive inside the casing.
This 1 TB version retails for $499.
The USB port can be used for an external hard drive addition or a printer to be shared over the network.
Specs
Wireless Data Rate: 200 - 540 Mbps
Range: 165 ft.
Compatibility: Wi-Fi (802.11a/b/g and draft 802.11n)
Frequency: 2.4 GHz or 5 GHz
Radio output power: 20 dBm (nominal)
Supported protocols: NAT, DHCP, PPPoE, VPN Passthrough (IPSec, PPTP, and L2TP), DNS Proxy, SNMP
Security: WPA, WPA2, and WEP (configurable for 40-bit or 128-bit)
Capacity: 50 users
Storage: 500 GB or 1 TB 7200-rpm Serial ATA HDD
Weight and Dimensions (US): 3.5 lbs., 1.4" x 7.7" x 7.7"
Weight and Dimensions (Metric): 1587 g, 36.3 mm x 197 mm x 197 mm
Ports: 4 - Ethernet (10/100/1000BASE-T) and 1 - USB