Manual Overides 

Series SD "Declutchable" Manual Override For either Double Acting or Spring Return Applications	Series SRD "Non-declutchable" Manual Override. Only for Spring Return Applications
ISO 5211 and Actuator Manufacturers Cross Reference Order Information Sheet

Now selected sizes available in Stainless Steel -- contact the factory for details! Sandwich manual override gear operators are used with valve actuators to provide manual operation of the valve in the event of actuator failure or power loss. These gear operators are mounted (or "sandwiched") between the valve and the valve actuator.  Click here for an example of "sandwich installation" DynaTorque manufacturers two types of "Sandwich Overrides": The Series SD is a Declutchable Worm Gear Manual Override.   The Series SRD is a Non-Declutching Worm Gear Manual Override.  This device can only be used with Spring Return style valve actuators and is generally a bit more economical than the Series SD as it does not have a declutch mechanism. Both styles require properly sized handwheels for the manual override function.