Truth Entrygard Dual Arm Operator. We would expect you to find 20755 on the linkage arm, which measures 3-3/4" overall length. Other common numbers we would expect to find are 31538, 31539, 30841, 30842, 30472, 30470, and 20755. Also known as a TH-24032 or TH-24033

To determine hand of operator, if your sash lock (window lock), is on the left, you would use a left hand operator. And if your sash lock is on the right, you would order the right hand operator.

3-3/4" link dimension, offset up. For offset down order Wi1520

Order Wi1510 if your link dimension is 4-7/16" stamped 20810.
Order Wi1515 if your link dimension is 2-7/8" stamped 20748.

Left hand shown.

PART # HAND
WI1516R RIGHT HAND
WI1516L LEFT HAND

Truth Entrygard Dual Arm Operator