The ELS-100FLG electro-optic liquid level sensor with flange mounting is used with sheet metal or molded plastic tanks where threaded installations are not practical. These compact sensors feature a thread-free design with minimal prism intrusion that ensures easy installation in thin-walled vessels. They are ideal for use in applications where exposed threads cause potential bacterial breeding and contamination. Sensors simply slip through a .75-in. hole to be manually tightened and have a gasket to form a tight seal. Gems Sensors, One Cowles Rd., Plainville, CT 06062-1198. Tel. (860) 747-3000; fax (860) 747-4244;