3/4" x 3/4" Mount Block

Emcon mount blocks have C'Bored holes and location dowels. They come in steel or aluminium. Metric or Inch series with multiple length options.
Inch series have C'bores for 5/16" SHCS and dowel holes are 5/16"
Metric series have C'bores for M8 SHCS and dowel holes are 8mm
 
Used to keep holes in larger items on the same plane. Reduces machining operations and reducing cost.