Hmm , not sure . I recall a manual for an early Siemens flip phone and was somewhat surprised to read (similar) that ' of the 350 people ( of 600 ) whom tested positive for BRAIN CANCER , that the problem was not consider to be their phone because the BRAIN CANCER developed on the 'other side of their head' and was not associated with (their particular model) of cell phone . I have personally used the speaker phone at a distance since reading that Siemens flip phone manual , believe or not , your choice I guess , regards and good health .