Ultrex is neither plastic nor metal, but rather an energy-efficient, durable, pultruded fiberglass material that is virtually maintenance free. Ultrex is used in the sills of all Marvin doors and glider windows.

To keep your windows and doors operating smoothly, periodically remove dust and debris from the Ultrex sill. Ultrex’s finish can be cleaned using warm water and a non-abrasive household cleaner.
 


Ultrex sills are usually beige in color, but can also be bronze in tone.

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During the 1950s, Marvin’s small sales force criss-crossed the Upper Midwest in...

During the 1950s, Marvin’s small sales force criss-crossed the Upper Midwest in Chevrolet station wagons, signing up independent local dealers to distribute Marvin windows. During this time, the ...