12+8 (Pf) bright red, proof \"Dresdner castle\" on greyish typewriter paper, line perforation L 11 1 / 2, with two further variety the Zwinger stamp and a pair the 20 penny numerals on properly franked local registered letter. Photo expertize Jens R. Kunz BPP. These trial proofs on cover belong to the large East Saxons rarities.