A tether device is provided which includes a first wristband to which a retracting mechanism is attached. The invention also relates to the compositions containing such a compound for the dyeing of keratinous fibres and the method for using said compositions. The multiplexer selects a data bit from the data sample word based on the clock sample word. The wireless interface module can establish one or more wireless links with one or more peer EIR terminals, to join a wireless network which is collectively formed by the peer EIR terminals.