Profile: Effox - Flextor design and manufacture of dampers and expansion joints for use in flue gas and process air handling system. We are ISO 9001: 2008 certified. Our damper offers guillotine/slide gate dampers, louver dampers, diverter dampers, stack isolation dampers, poppet dampers and radial vane dampers. Our guillotine dampers are used when tight shut-off is required to isolate specific portions of a flue gas system for maintenance or by-pass purposes. Our butterfly dampers as small as 6" diameter to as large as 120" diameters. Butterfly dampers can be used for modulation when precision is not critical. For more precise flow control applications, opposed multi-blade circular louver dampers can be used.