Comments about Observation Device:

It can hear the smallest whispers from across a quiet room, but if you are in an area with background noise, forget it. If in an area where volume around you or your target changes, you will be nearly deafened by the louder sound while trying to listen to the quiet. It's area of effect is too great for accurate observation. For the price, I suppose it is a good deal for outdoorsmen wanting to listen closely to bird-calls, but if your purposes are more precise, I suggest a different device.
On a different note: It can be taken down to a more portable size and be put back together with extreme ease for portability purposes.

Comments about Observation Device:

Works great for listening to people whispering at levels too low for the ear, but when outside, it picks up too much background (outside) noises. It is pretty rugged and the ability to quickly remove the dish (and put it back on) makes it good for stowing. In areas where the noise level may change frequently, it is almost useless - you have to turn its sensitivity up to hear the quieter sounds and then get blasted by deafening noises when a sudden burst of louder noise comes through the headphones. If you are into listening to birds, you can listen to the details of their squawks, but if you want to listen to an open window or a passing deer in a lively hunting ground, you will be disappointed.