Design "Rome" 1906 International Reply Coupon as block of four 30 C. Bulgaria. This block of International Reply Coupons belong to the scarcest postal stationery and is a key item of any exhibition collection. The importance and real value is still very much underestimated - highlight of every postal stationery or country collection. This offer comes from the collection king fuad - this block of four is probably unique in private hands (Image)