Auction 333-341 Nigeria, Cameroon, Sudan & Worldwide Postal History - Day 4

International Reply Coupon 1912: Rome type IV, 3 d. green-blue & pale-olive, imperforate Proof block of four, large margins all round, printed by V. Benziger & Co. Switzerland, fresh vibrant colour. The reverse has instructions in four language and states: "This coupon can be exchanged for a postage stamp of the value of 25 centimes or the equivalent of that sum in countries which have adopted the arrangement.".  Very fine and rare.
Note: The Rome type were named after the U.P.U. convention leading up to the introduction of the design.
Reference: The Postal Stationery of Nigeria, by Peter Hørlyck, illustrated on pg. 233.