I don't know anything about this product, but I can tell you a story . . . we tested a transmitting device for a company a while back. It failed. It turned out that my husband's air consumption rate was simply lower than anything the company had envisioned a diver could have, so the transmitter turned off because it thought he was done diving. If such a device could be set for what air consumption rate it would use as a trigger, it might be better than nothing . . . but to need it, you have to have quit breathing AND lost your buddy. That's a lot of really bad things to happen on a single dive. If you are a habitual solo diver, it might pencil out better.