Garmin Descent T1 Transmitter

Garmin brings you air integration when you pair the Garmin Descent T1 Transmitter with the Garmin Descent Mk2i Wrist Dive Computer, Titanium. When paired together, you can now monitor your tank pressure, remaining air time, and air consumption rate all right on your wrist. When you pair additional T1 Transmitters with your Mk2i dive computer, you can monitor your dive buddy’s air as well thanks to Garmin’s SubWave™ sonar technology. Dive safer. Dive smarter. Dive Garmin.
 
Garmin Descent T1 Transmitter Features:

Dimensions: 3.33″ x 1.44″ x 1.44″ (84.50 x 36.52 x 36.52 mm)
Battery: 3 V CR123A lithium, up to 100 hours
7/16″ thread type
Operating temperature: 0 to 40°C (from 32 to 104°F)
Transmission range: Up to 10m (33ft)
Depth rated to 110 meters
Reports pressure up to 300 bar (4351 psi)

Garmin Descent T1 Transmitter Documentation:  

Garmin Descent T1 Transmitter Owner’s Manual