Product Description This casement operator features a hardened steel arm that is driven by a worm gear mechanism. The square body style includes a crank handle and a 3/8 in. spindle. Easily mounts on the right side of your window when viewed from the inside. From the Manufacturer This casement operator features a hardened steel arm that is driven by a worm gear mechanism. The square body style includes a crank handle and a 3/8 in. spindle. Easily mounts on the right side of your window when viewed from the inside.