Braun disposable lens filters LF40US enable accurate and hygienic temperature taking. It’s important that the Braun ThermoScan lens filter is replaced every time a reading is taken. Disposable 40 piece lens filters ensure hygienic use without having to clean or disinfect the sensor and virtually eliminate cross contamination. What’s more, fitting a new Braun lens filter each time ensures that dirt or ear wax don’t build up and clog the sensor window, which could lead to inaccurate temperature readings.