The latest generation of the SIMB, the SIMB3, was designed to be more light weight, less expensive, and more reliable. It is a two-piece, single hull, spar type buoy (Figure 3). It possesses the same core sensor types as the previous versions (acoustic rangefinders, barometer, air temperature sensor, temperature string) but has a higher resolution (2 cm spacing) temperature string. A major advantage is that assembly can be accomplished by just one person and without the use of tools.