Truth 40773 white nylon multipoint lock keeper used with Maxim Interlock roller system.
3 sets of mounting holes allow for maximum adjustment 

Measurements:
Length: 1-3/4" (44.9mm) 1.767
Width: 5/8" (15.9mm) 0.626
Leg Length: None, Flat bottom
Overall Thickness: 0.228 (5.79mm)
Handed: Yes, Left & Right as Shown 
Material: Nylon (plastic) 
Color: White 

Priced and sold each.

Markings: 40773, Part number stamped on back (underside)
The best way to figure which one you need is the number stamped on the bottom OR the length of the leg in millimeters. (mm)

Related Parts:
556084 - .228 Thick, Flat Bottom RH
556085 - .228 Thick, Flat Bottom LH
556086 - .278 Thick, 1/16" Legs RH
556087 - .278 Thick, 1/16" Legs LH
556088 - .331 Thick, 1/8" Legs RH
556088 - .331 Thick, 1/8" Legs LH
556090 - .371 Thick, 5/32" Legs RH
556091 - .371 Thick, 5/32" Legs LH