MECOS frequency device

[Gordon JC Pearce]

>>
>>> Likely way off topic, but I acquired some sort of frequency device in
>>>an auction junk box. It's a well machined device made by MECOS, made
>>>in W.Germant. It's about 2" square by 1/2" powered by a Li. battery
>>>and has micro-switches labelled 3 hz, 7.8 hz, 14.0 hz and a small led
>>>that flashes at the selected frequency. Anyone have any idea what it
>>>might be ?
>>>

Those sound awfully like brain wave frequencies.  Can you plug anything 
else in?  Like maybe a pair of sunglasses with LEDs in the lenses?

Gordon.