Braun ThermoScan Lens Filters 40 Pcs Help avoid pollution transmission if replaced before each measurement, latex and bpa (bisphenol a) - free for safety improvement as it is compatible with all ear temperature scales there are 40 disposable covers covering the disposable probe for each box. The installation of a new brown cleaning cover ensures that no dirt or ear wax builds up and fills the sensor window, which can lead to inaccurate temperature readings. A safe and effective product to use.