The In-Situ Level TROLL 400, is a non-vented water level, pressure and temperature logger and part of the In-Situ Level TROLL family. The Level TROLL 400 is available in four pressure ranges and is ideal for monitoring situations when barometric compensation is not required, or practical. However, the TROLL 400 can be configured with a In-Situ BaroTROLL to compensate for barometric pressure fluctuations. The TROLL 400 is ideal for applications such as, long term monitoring, storm water management and stream gauging.