This is the Apeks Wireless Transmitter 

Features:

• Hoseless gas pressure transmission for the Apeks DSX, Aqualung i450T and i750T and any of Shearwater computer
• Once set, the transmitter is permanently paired and will not accidentally pair with other computers
  
• Battery is user changeable and commercially available
• Nitrox compatible up to 100%

Apek's Transmitters, used in conjunction with a compatible wrist computer, allow you to monitor current pressure and gas time remaining without a stiff high pressure hose, while providing a more streamlined profile.