Window Operator S1068 Amesbury Truth Casement Dyad Operator Link Offset Up 7/16 Inch Truth Hardware Replacement Prime-Line 9-1/2 in. single-arm Left-Hand Casement Operator TH 23021 Truth Hardware Dyad Ellipse Casement Window Operator With 5" Link Arm It is made of heavy-duty diecast zinc. The steel arm, worm drive and gears are protected with a corrosive resistant finish and it opens to a full 90 degrees. When installing, the housing easily fastens down to the window sill Operator components include: high pressure diecast zinc case; handle and knob in baked enamel finish; hardened steel arm, drive worm and gears are protected with corrosion resistant finish; plastic roller assures smooth operation; operator provides a full 90Degree window opening and disconnects easily from the sash.