A rotary radio frequency, RFID, switch, comprising: a base member which defines an axis of rotation of the switch and which base member has a first major surface thereof and which base member includes a plurality of RFID tags mounted to and circularly distributed around the first major surface of the base member; the base member being formed with a first cam arrangement , which first cam arrangement comprises a plurality of axially-extending and circularly distributed indentations , which indentations correspond in number to that of the plurality of RFID tags ; a cover member arranged to overlie and be biased into engagement with the base member , which cover member is RF-masking and is circularly distributed with a plurality of RFID tag covers , wherein said covers number at least one less than the number of tags ; and which cover member includes a second cam arrangement , the RFID switch being characterised in that : the second cam arrangement comprises a plurality of axially-extending and circularly distributed indentations which correspond in number to that of the indentations of the first cam arrangement and which are shaped to fit with the indentations of the first cam arrangement; the cover member including an RF-transparent window ; the switch being arranged such that the relative rotation between the cover member and the base member about the axis of rotation causes the first and second cam arrangements to axially separate and return the cover member and base member , whilst concomitantly exposing individual RFID tags of the plurality of tags to the RF-transparent window . a base member which defines an axis of rotation of the switch and which base member has a first major surface thereof and which base member includes a plurality of RFID tags mounted to and circularly distributed around the first major surface of the base member; the base member being formed with a first cam arrangement , which first cam arrangement comprises a plurality of axially-extending and circularly distributed indentations , which indentations correspond in number to that of the plurality of RFID tags ; a cover member arranged to overlie and be biased into engagement with the base member , which cover member is RF-masking and is circularly distributed with a plurality of RFID tag covers , wherein said covers number at least one less than the number of tags ; and which cover member includes a second cam arrangement , the RFID switch being characterised in that : the second cam arrangement comprises a plurality of axially-extending and circularly distributed indentations which correspond in number to that of the indentations of the first cam arrangement and which are shaped to fit with the indentations of the first cam arrangement; the cover member including an RF-transparent window ; the switch being arranged such that the relative rotation between the cover member and the base member about the axis of rotation causes the first and second cam arrangements to axially separate and return the cover member and base member , whilst concomitantly exposing individual RFID tags of the plurality of tags to the RF-transparent window . the second cam arrangement comprises a plurality of axially-extending and circularly distributed indentations which correspond in number to that of the indentations of the first cam arrangement and which are shaped to fit with the indentations of the first cam arrangement; the cover member including an RF-transparent window ; the switch being arranged such that the relative rotation between the cover member and the base member about the axis of rotation causes the first and second cam arrangements to axially separate and return the cover member and base member , whilst concomitantly exposing individual RFID tags of the plurality of tags to the RF-transparent window . <EOS>