Biomark offers pass-by and pass-through PIT-tag antenna designs. Pass-through antennas are mounted in an upright orientation designed for tagged subjects to pass through the antenna opening. Ideally, the tag is detected throughout the antenna opening as well as some distance on either side of the opening. Pass-by antennas are mounted in a flat orientation designed for tagged subjects to pass over the antenna. The tag is detected above the housing or perimeter of the antenna when oriented horizontally.