The T3-Mini is a miniature version of the Tracker3 measuring 1.73"x1.12"x0.215" (44x29x5.5mm) and weighing 5.5 grams. It has all of the software features of the other Tracker3 models, and provides 4 analog inputs and 13 general-purpose digital I/O pins. Its serial ports can be configured for RS-232 or TTL operation.

Technical information can be found at the link below:

Tracker3 Series APRS Tracker