A mammal vaginal implant transmitter is inserted into the vagina of an impregnated animal using a plastic silicon wing designed for estrus timing of livestock. A mammal vaginal implant transmitter is used to indicate a birth has occurred by change in the transmitter pulse rate. It uses a reduction in temperature or a cessation in activity to sense that the transmitter has been expelled. This technique is used primarily with ungulates. Field range is approximately one-third to one-half that of a neck collar with an external antenna.

Series	Weight (grams)	Life (days)	Description
M3900	11-50	32-766	Flexible silicon wings, large and small sizes