About the Transmitter
The transmitter is made by North Star Science and Technology: http://www.northstarst.com, or check facebook: https://www.facebook.com/NorthStarScienceTechnology. It is a small rectangular backpack that attaches to the eagles via teflon straps. It weighs about 55 grams, or roughly 2 ounces, and is solar-powered. Northstar's website lists the operational life as indefinite, but probably 2-4 years: our eagle biologist had one last as long as seven years.
For more information about the transmitter, please see this blog post.