560 Series Tilt Latch in Black - Pair.

Fits better bilt, Aluminum 540 series Thermal Break window.
Left & Right Handed.
The Top rail has to be removed and these slide into two grooves, then replace top rail.
This will work as a replacement for part 83-623.

NOTE: This Slide latch looks a lot like Others Please compare measurements and Pictures to be sure.

Priced and sold in pairs.