Tilt window latch
A quick learner from Zirconia says:
September 4, 2016
This is the top cap that you slide to release the window to tilt inwards.
Tom from SWISCO responded:
September 8, 2016
Thank you for posting. I'm afraid we don't have an exact match for this latch. To be honest, you may be better off substituting with a surface mount tilt latch. These are different than the others in that they just screw on. We have a video tutorial that shows how we do this. We find it to be an easier solution for sashes like yours. Let me know what you think!