This is a pair of Zanzibar 1895 SG 11 & 12, the 4 Annas Olive and Slate Green, respectively.

The Slate Green shows a RARE variety, that being that it has an ARABIC R in Zanzibar, which is unlisted.

These little beauties are in Mint Very Fine Condition and are valued at L83+ in the Stanley Gibbons Catalogue!