A subcutaneous transmitter is surgically implanted under the skin of the reptile. A small incision is made and a long hollow needle is inserted under the skin where the antenna will be placed. The antenna is inserted into the needle which is used to pull the transmitter into place. The incision is closed with 3 or 4 stitches. Training is required to surgically implant the transmitter and there is a recuperation period for the reptile. Subcutaneous transmitters need to be light. Therefore, a small battery is used which results in less power output and somewhat reduced field range.

Series	Weight (grams)	Life (days)	Description
R1605	0.5-1.2	20-392	Smallest sizes, reduced power output for longer life, minimum potting for lowest weight., silver oxide battery, flat rectangular shape. Limited frequency availability.
R1600	1.0-3.6	15-468	Small size, standard power output for normal life, normal potting for durability, silver oxide battery, flat rectangular shape.