The Model 3500 AquaVent water level data logger from Solinst Canada Ltd. uses a vented pressure transducer for reliable, accurate data logging of water levels in shallow surface water and groundwater applications. It combines a pressure sensor, temperature thermistor and data logger within a 7/8- by 7-inch stainless steel housing. Permanent desiccants mean there is no need for replacement — providing moisture protection for the lifetime of the instrument. The vented pressure transducer is made of Hastelloy, making it durable and accurate in a wide range of temperature and monitoring conditions. The batteries, which are user-replaceable, can last eight to 10 years (based on one reading per minute). It has options for communicating strictly with Solinst software and accessories, or integrating into a telemetry system, SCADA/PLC system or network using SDI-12 or Modbus protocols. 905/873-2255; www.solinst.com.