SG 372 N21 (10) 2½d Blue. An Unmounted mint control K17 perf example with perf type 2A. The VERY RAREST control being by far the rarest of all the 2½d's in this perfect condition. Dealers list price for this stamp mounted mint is just shy of a grand but this rarity is both unmounted and unfolded and although i'm not an expert or dealer i haven't seen one of these advertised before in such great condition.... The item "KGV SG 372 N21 (10).A rare Unmounted mint control K17 perforated" is in sale since Friday, April 30, 2021. This item is in the category "Stamps\Great Britain\George V". The seller is "iahardha_0" and is located in Fareham. This item can be shipped to United Kingdom.