my mum just sent me this she works for the mhra its like a government thing (i really should listen more to what she does!!) there is a problem with part of them and if you have one you should contact the manufacturer. if you click on the link and go down to the bottom and download the pdf it explains www.mhra.gov.uk/Publications/Safetywarnings/MedicalDeviceAlerts/CON085140
hope that helps