Nexus Strike plate keeper, Raised ½" x 7" length - YDI
The nexus keeper comes in several styles and heights
Styles: Flat, Raised with wide base, Raised with Narrow base

Raised Strike Plate Keeper for mortise lock 
Length: 7 inches
Width: 5/8 inch
Height: 1/2 inch
Markings: M5B

Related Truth Parts for Nexus Mortise Lock Keepers
15345 - Nexus 2-point Sliding Door Mortise Lock
33187/15341 - Stainless, Flat Keeper for Mortise Lock - 6.5" length