The SmartBob2 SS sensor from BinMaster Level Controls measures the level of solid material below a liquid surface, such as in interface applications. It can be used in tanks where solid material settles at the bottom of a tank, such as for measuring the level of settled salt, sediment or sand under water, making it an alternative to relying on sight tubes. It can be used in any application where solid material needs to be measured under liquid in water treatment or wastewater facilities. The sensor drops a weighted bob through the liquid; when the bob comes into contact with solid settled material at the bottom of the tank, it retracts and sends a measurement to a control console or a PC loaded with eBob software. 800/278-4241; www.binmaster.com.