This is a rare pair of SOUTH AUSTRALIA 11a stamps, an error, printed on both sides. This horizontal pair is pale red, rouletted and pen cancelled.. They have been certified by the British Philatelic Association.  The 2009 Scott catalog price is $2050.  And of course it is also listed in Stanley Gibbons' catalog (24ab). This pair of stamps is a valuable addition to any stamp collection, especially for those interested in South Australian stamps and their history. The stamps have been well-preserved and are in good condition,  You won't see it offered again in a long time.. Don't miss the chance to own this piece of philatelic history!