This cable operated damper by Metropolitan Air Technology is an excellent addition to your HVAC system. The Roto Twist 150 RT-150 model has a 10 inch diameter and is round in shape. With a wired feature, this manual damper can easily be operated from a distance. It belongs to the HVAC Dampers category and is perfect for business and industrial settings. The brand name is clearly mentioned in the aspects section, along with the model number.