This is a universal louver operator in aluminum finished diecast construction. The mounting holes are 4-3/4 in. or 3-7/8 in. on center. 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 in. to 5-5/16 in. L to accommodate the needs of installation. It comes with a matching Tee handle that fits the 5/16 in. spindle.