 The Time Capsules up to the 4th generation measure square, and high, slightly larger than the AirPort Extreme Base Station and close to the first generation Apple TV in volume.Its size is partly due to the inclusion of an internal power supply, which eliminates the requirement for a separate external power supply, enabling a direct connection between the household power outlet and the back of the Time Capsule.The June 2013 release of the 5th generation models features a name change to AirPort Time Capsule, and a redesign with measurements square, and high.