I just got 2 of theses guys that were supposed to be Ground Intrusion Detection devices used in Vietnam.

I would like to have more specs and history on them. The only thing I found so far was very general:

I quote:
"Scatterable sensors. These were small devices, mostly seismic.
They consisted of a seismic detector, a transmitter, and internal antenna, and a battery in a fiberglass or plastic case made to look like a broken branch, a big leaf, or other piece of forest litter. One type of sensor was designed to look like -- I am not kidding -- animal droppings. (Most of these things were Seismic Intrusion Detectors -- SIDs. These latter types were immediately named "TURDSID" by the guys using them.)
They were usually delivered by air, just dump a batch of them out along a trail, road, or in a suspected base camp area.
Because they were small, their batteries were small and transmitters were small. Battery life was not long -- a few days."

Thanks for your Help.

Well, ya got me, but it sure does look like a turd!

It does, doesn't it....but that was the purpose.
I have two....one "new" like on the picture, with the plastic ring on and one without. The plastic ring covers a little plastic "needle" that you can remove. I guess that was a way to "arm" these things...