This torque bar operator is designed to mount in the center of your window sill and a square 1/4" x 1/4" torque bar passes through the center of it.  When you turn the handle (sold separately), the torque bar is turned and that opens or closes and your window.

Dimensions:

• Foot: 1-13/32"  x  1-1/8"    
• Screw Hole Spacing: 1" OC for long side and 11/16" OC for short side
• Torque bar shape: 1/4" square 
• Case height including foot: 1-9/16"
• Case width: 1-1/4"
• Stem length total: 7/8"
• Stem length (smooth part): 9/16"