U-T-C’s U-D-I, is an underwater communications tool, safety device and dive computer, all rolled into one wrist-mount unit that seamlessly connects you to the boat unit. The U-D-I offers three emergency signals: the “S-O-S” alerts other U-D-I-equipped divers if you’re in distress. If you suspect your buddy is in trouble, you can send a “Remote S-O-S,” which activates his unit. Finally, the U-D-I “Homing” feature provides graphical directions to fellow divers or back to the boat. The U-D-I also allows you to transmit pre-configured messages to each diver in a network of divers and to the boat’s base unit, up to 550 yards away. As a dive computer, the U-D-I offers full nitrox capabilities and a digital 3-D compass. The Bottom Line: The U-D-I is an all-in-one diver’s device, designed to deal with in-water emergencies and situations.