A counting device for counting mechanical inputs comprising: a rotatably mounted first counting wheel arranged to rotate by a predetermined amount for every input that is to be counted; and, a second counting wheel in mechanical communication with the first counting wheel, and at least in part overlapping the first counting wheel, wherein the second counting wheel and/or the first counting wheel are at least in part transparent; whereby the mechanical communication between the first counting wheel and the second counting wheel comprises a rotation mechanism configured to drive the second counting wheel a predetermined amount when a predetermined number of inputs has been reached. A counting device for counting mechanical inputs comprising: a rotatably mounted first counting wheel arranged to rotate by a predetermined amount for every input that is to be counted; and, a second counting wheel in mechanical communication with the first counting wheel, whereby the mechanical communication between the first counting wheel and the second counting wheel comprises a locking mechanism comprising a formation on the second counting wheel configured to engage with a housing peg, a first counting wheel formation or a lock, and a rotation mechanism configured to drive the second counting wheel a predetermined amount when a predetermined number of inputs has been reached.