6 Garmins Astro 320 GPS Dog Tracking System with 3 x T 5 Collars, Screen Size: 3.5 Inch, we have 6 units, five retail boxed and one unboxed. Some units were never used or used once and returned to box. Selling as is, they have been sitting on a shelf for the past 5 plus years.

Key SpecsHandheld (Astro 320): High-sensitivity GPS/GLONASS receiver, tilt-compensated 3-axis electronic compass, barometric altimeter, basemap (expandable with TOPO maps, BirdsEye satellite imagery via optional subscription/microSD), tracks up to 10 dogs simultaneously. Display: Vibrant, sunlight-readable 2.6-inch (diagonal) 65K-color TFT (160 x 240 pixels; approx. 1.43" x 2.15").

Dimensions: ~2.4" x 6.3" x 1.4" (without antenna); weight ~9.2 oz with batteries.
Power: 2 AA batteries (NiMH or lithium recommended); up to ~20 hours.
Waterproof: IPX7. Includes standard (~5") and extended-range (~13") antennas.

T5 Collar: Top-mounted high-sensitivity GPS/GLONASS transmitter + flexible braided stainless-steel VHF antenna (keeps upright for better reception). Waterproof to 10 m. LED beacon lights (controllable from handheld), rescue mode (slows updates when battery is low). Range: Up to ~9 miles (line-of-sight, flat/open terrain; less in mountains/trees/canyons—often ~4 miles practical). Updates as often as every 2–5 seconds.
Battery: Rechargeable Li-ion; ~20–40 hours depending on update rate. Weight ~9.3 oz with 1" collar strap (designed for larger breeds; T5 mini available for smaller dogs). Dimensions (transmitter): roughly 3.5" wide x 1.75" high x 1.85" deep.

The combination system shows dog location/trail on the map, compass pointer to the dog, distance, and status. Pairing is done via proximity or ID number. It supports multiple handsets and is compatible with certain older TT15-series collars for tracking only (training functions require other handhelds).