Pre-2010 Mastic Window (not the Mastic Window Company Today)
A handy person from Albany, NY says:
October 2, 2017
Locking mechanism that holds the tilt in and tilt out function in place for cleaning. No Model Numbers available on the window.
Paul from SWISCO responded:
October 5, 2017
Please check out our 26-228 and 26-229 top tilt latches and compare our measurements to yours. These were used by Mastic window company. Let us know if these will work.