Silverline 4000 series concealed internal tilt-in latch set for top sash
White (Blue White)
Latch Width: 3/4 inch
Latch Length: 3-1/8 inch
This is a left and right hand set.
Held in place with screws and appears to be reversible.
Priced and sold in pairs.
Note: 503068 & 503078 Look very similar, Please compare yours with pictures.