96 (87) 1897 2½ on 1a indigo and red Sultan Seyyid Hamed-bin-Thwain of Zanzibar surcharged SG Type 13 (Scott Type b) and overprinted "British East Africa" SG Type 8, this is the scarce key type which only occurred on 10 positions in the setting of 60, tied to small piece by "Mombasa" squared-circle cance.