CSA Catalog 6-PPa (SC#6P5), PAIR 5¢ blue plate proof, positions B85/B86 from the only known sheet (since broken up), 1 stamp signed Robson Lowe, the other PA Kaufmann, copy of 1976 PF Certificate for the discovery sheet (Robson Lowe). The proof has a yellow cast compared to the regular issues, but is difficult to determine without a reference copy. CCV and SCV $150 for a single. $325.