Mongolia 1926 New Currency 50m error of colour black and yellow used -

Mongolia 1926 New Currency ...
Mongolia 1926 New Currency 50m error of colour black and yellow used - Sold on eBay Sep, 25th 2019 for $2,550.00
50m. in black and yellow , the issued colour of the 40m., used with part Ulan Bator cds of 1927. This very stamp, illustrated on page 217 of Hellrigl's book, was sold at David Feldman auctions in 1983 for 9,000 SwFr. The reverse has annotations from Peter Holcombe and his initials, there is a heavy vertical crease. Wolfgang Hellrigl only records two examples. All invoices over £100 will only be sent by registered mail, please choose the international signed for option...