Siemens GCA121.1U/B Spring Return, 160 lb-in (18 Nm), 24 Vac/dc, 2-position Control, 90 sec Run, Bulk 8

Siemens GCA121.1U/B Spring Return, 160 lb-in (18 Nm), 24 Vac/dc, 2-position Control, 90 sec Run, Bulk 8. The Siemens OpenAir GCA Series Actuator is a spring-return electronic damper actuator that is rotary and direct-coupled. Designed for digital and analog control of dampers in constant and variable air volume installations.