Plastic Vent Latch With Metal Tab/Wire
(This is sometimes also called a night latch)
Restricts the opening of the window
Usually 2 per sash

Measurements:
Base length: 1-5/32 inches
Base width: 9/32 inch
(See images for additional measurements)
Slot Size (that it fits into): 0.17 inches x 1.063 inches

Fits most double-hung, single-hung and sliding windows using this design

Priced and sold each

NOTE: Several of these look similar, Please compare sizes, measurements