The Braun Thermoscan lens filters are suitable for all Braun thermoscan ear thermometers. They prevent the lens from scratches and impurities which may effect the accuracy. They must be replaced after every use to ensure hygiene which will practically eliminate the risk of transferring germs. These lens filters come in a pack of 40. Use only with Braun certified lens filters for accurate readings. Designed to assure accuracy and prevent cross,contamination with Braun ThermoScan home use thermometers. Braun ThermoScan Lens Filters , 40 Pack Fits all Braun ThermoScan models.