I ordered LF40 (LF20) but received PC40 (PC20). There seemed to be very little difference in a side-by-side comparison of the the LF20 and PC20 package and filter. They also seemed to work about the same in my Braun thermometer. My guess is that it was only marketing/packaging for different markets.Get more detail about Braun LF40 Thermoscan Ear Thermometer Lens Filters (40 pack).
