Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Mexico - 1929, Eagle in Flight, perforated (L12) proof of 25c in brown and green, printed on watermarked paper CORREOS MEXICO, block of four, full OG, NH, VF and very rare, only 50 proofs were printed and this item is one of two known blocks of four, Sanabria (1966) #12, C.v. $1,000 as singles, Est. $2,000-$2,500, Scott #C3