The CDO Range from Link Controls
The CDO range are all sprung barrel assemblies, a sprung barrel assists the lift of the door and generally enables a smaller door operator to be used. For sprung shutters the Foot and Flange mounted CDO range of operators are the most popular, using a drive chain or gear set to transmit the power to the barrel.
CDO Handing Information
The diagram below illustrates the handing of the CDO operators, the drawing is from a top view, this should distinguish whether your operators is '1A' or '1B' depending how the operators is mounted.