Apple Watches may be able to change their interface based on which ‘smart band’ is attached — Apple World Today

The smartwatch would detect an identification of the band, which can serve as an input to initiate actions performed by the Apple Watch. For example, a type, model, color, size, or other characteristic of a band could be determined and used to select a corresponding action performed by the electronic device. 

Identification of the band could be performed by components of the Apple Watch that also serve other purposes. Existing sensors, communication elements, and/or detectors could be used to detect and identity a band connected to the smartwatch. The Apple Watch could respond to the identification of a particular band by performing particular functions, such as changing an aspect of a user interface or altering settings of the device.