6 1/2p Cylinder Proof

6 1/2p centre band cylinder 4. block torn from a master double pane. this was provided by Harrisons the printers, to Barbera Baker, editor of Stamp Collecting, as a sample of an upcoming issue.the no dot cylinder is the same as issued, but 'Dot' cylinders had to be torn from master double pane, thus providing a unique cylinder block 'PROOF'. I have several of these, but only 1 per cylinder, all thus unique items.