H 3546 is a universal louver operator in aluminum finished die-cast construction. The mounting holes are 4-3/4 or 3-7/8 in apart. It is a reversible non-handed design that can be used on either left or right handed installations. The universal link arm comes with break-off points with holes every 1/2 in providing a link arm 1-13/16 to 5-5/16 in long to accommodate the needs of installation. It comes with a matching tee handle that fits the 5/16 in spindle.