Published: 16:27 EDT, 21 January 2014 | Updated: 17:04 EDT, 21 January 2014

It may look like an average piece of dog feces - but in fact, this is a complex military transmitter used throughout the Vietnam War.

Known as the 'T-1151 Dog Doo Transmitter', it was used as a homing beacon during the Vietnam War.

It emitted a warning when movements occured, allowing US Military bosses to monitor shipments, or find a soldier in need of rescue.

The transmitter is a homing beacon that sends out a signal to those monitoring an indicator - or someone in need of rescue.

Inside is a transmitter than can be used as a homing beacon, or transmit morse code messages

The Doo radio transmitter, officially known as a T-1151 radio transmitter, is a radio transmission device camouflaged as a pile of animal droppings or, in its most common form, a large single fecal dropping from an animal indigenous to the area of intended use.

it transmitted a radio signal that helped aircraft pinpoint key enemy ground sites for strikes or reconnaissance.

It was also used as a beacon for troops in distress.

Initially developed by United States military intelligence about 1970, the Doo transmitter was a homing device camouflaged as dog or monkey feces for use in Vietnam.

'This transmitter is a homing beacon that sends out a signal to those monitoring a signal of someone in need of rescue,' says the US Air force Military Museum, which holds them unique item.

'It is camouflaged to resemble the excrement of a medium size dog or other animal.'

Dropped along the Ho Chi Minh trail by air, the device transmitted a warning when supply movements occurred during the night.

The effectively camouflaged beacon was positioned throughout the jungles of Vietnam, where it transmitted a radio signal that helped aircraft pinpoint key enemy ground sites for strikes or reconnaissance.

Initially developed by United States military intelligence about 1970, the Doo transmitter was a homing device camouflaged as dog or monkey feces for use in Vietnam.

The U.S. Department of Veterans Affairs says the Vietnam War (1964-1975) involved over 8.7 million U.S. service members worldwide.

Over 3.4 million were deployed to Southeast Asia.

The United States suffered around 58,000 battle or "in theater" deaths during the Vietnam War.

Vietnam and neighboring countries like Cambodia and Laos suffered far higher death tolls, many of which were civilian.

There are around 7.2 million U.S. Vietnam veterans still living.

While several veterans of World War Two have been elected to the White House, the Vietnam conflict has yet to produce an American president.

The device often had a peat moss crusted shell.

The signals were monitored by a variety of agencies, including the CIA.

'At just over four inches long and three-quarters of an inch in height, this inconspicuous spy tool was small enough to be carried easily,'  says the Gale Encyclopedia of Espionage & Intelligence.

'It could send or receive radio messages, usually by Morse code.

'Because the Doo transmitter was often left undisturbed, operational life was often a function of the battery life of its nickel-cadmium battery array.

'This advantage was often essential when the transmitter was utilized as a homing device.

'Because the device gave the appearance of fecal matter, it was often left undisturbed and thus a retained high efficiency as a homing beacon even when planted days or weeks before a mission.'

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