| Image Thumbs | |
| Cert Num | 1278638 |
| Cert Date | 2014-03-06 |
| Catalog Number | 511a |
| Country | USA |
| Year | 1917 |
| Denom | 11c |
| Color | Light green |
| Grade | Ungraded |
| Description | Mint OGnh |
| Opinion | it is a genuine unused, o.g., never hinged, block of four, the top stamps No. 511, the bottom left stamps with transitional perf 11/10 at the bottom and the bottom right stamp perf 10 at the bottom. |
| Cert Link | http://psestamp.com/Cert/1278638 |