2100P Portable water testing equipment measure turbidity from 0.01 to 1000 NTU. Designed primarily for field use, the microprocessor based model has the range, accuracy, and resolution of many laboratory instruments. The instrument works on four AA batteries or with an optional battery eliminator. The instrument automatically shuts off after 5.5 minutes if no keystrokes occur, but can be turned on once again and the system will resume operation as if power has not been interrupted. The instrument with all standard accessories and the optional battery eliminator can be conveniently stored in a carrying case.