Manual operation can be accomplished with a hand crank, a pull chain with spring and wall clip, or a push rod attached to the operator unit. A fusible link option is available. Electrical operation utilizes motors which can be adapted to individual requirements. Pneumatic operators are also available.

Adjustable Dual Combination Blade (Drainable)
The Model 667/71 louver combines fixed and adjustable blades in a single frame. Air flow control is provided while the exterior appearance remains similar to most fixed louver installations. It provides excellent weather protection, very low water penetration, high free area and low air leakage. Blade edge and jamb seals are standard. The louvers can be controlled manually, electrically or pneumatically.

The cost of purchasing and installing Model 667/71 louvers can be significantly less than the cost of adding an adjustable louver to the back of a fixed wall louver.