3.75x7" "New Magic Slate Series #1 - Don Winslow Breaking The Sound Barrier." Produced by the Strathmore Co. ©1953 Frank V. Martinek. Cover includes illustration of jet plane on the back. Has bound-in 32-page storybook w/illustrations on every other page. Inside back cover includes ad for the "Magic Slate Code Book." Not to be confused w/the much earlier Don Winslow slate from 1935 that was issued as a newspaper premium. Missing wooden stylus. Cover shows edge/corner tip wear and the interior middle sheet of the slate adhered to the slate surface and has large splits that are obvious if the sheet is lifted. Age causes this problems on all examples. Fine overall.