This is the Motrak Models HO Scale Sand Loads for Athearn 50' Mill Gonodola (2-Pack).
Two sand loads for Athearn's 50' Mill Gondola
Motrax Product Number: 81204
These loads are made out of Hydrocal base with sand glued on top. Hydrocal plaster will break if dropped. If it breaks, you can use white glue to join the pieces together. If the sand load is chipped, you can spray diluted white glue with water and sprinkle some fine grain sand. Some loads might need some trimming for easy drop-in applications. To do this simply rub the sides with some fine sandpaper on a flat surface.