Here is a 1984 Topps Don Sutton #35 encased, blankback test issue.  It was used during the Topps design process and measures 2 1/2" X 3 1/2". 

If you are not familiar with these, you will have to look closely, as the insert picture is fully enclosed within its square/window.  It also has different cropping compared with the final issued card.  There were 66 cards on the design test sheet that only existed in proof form. It was cut slightly off-center, but with nice corners.

A rather unique team collectible for your Sutton, master set, or Brewers card collection  Regular issue card not included - just shown for comparison.

Please ask if you have any questions, and are looking for any other Topps test issues, proofs, or oddball player or team cards.  Thanks!