A new device (Fish Hawk TD) coming out from Fish Hawk which measures depth and temperature in 5 Ft increments down to 300FT. Can be attached to downrigger, dipsy, wire lead, or heavy snap weight systems to get depth and temperature for us guys that have simpler gear and boat setups. Looks like it is similar to a device that was around a few years ago that is no longer available. I believe it was a GTM-40. I see prices so far of $139-149. Five year battery life.