Z-Clip Fasteners sold in packs of 10, 20, 50 or 100.  Also included are small wood screws to help mount the clip.
 
Approx. Measurements 1-1/8" long, 5/8" wide, and a 3/8" offset.
 
Note - The standard hole in the fastener is 7/32".  The hole will need to be drilled out to accomodate a 1/4" screw for threaded inserts