1/35th Scale. Resin Cast.
These sandbag fronts were built on two most common tamiya kits. They will fit other M4A3 kits with a little work (shaving off details on the hulls or drilling or dremeling some spots in the back of the resin piece.)
Helpful Tips: A little carving or dremeling around the bow machine gun port where thin ovalish ridge on hull will help the fit.