German East Africa 1905 Yacht Postal Stationery Ei P18 Ei P19 Ei P20 (front) Ei P20 (rear) Ei P21 (front) Ei P21 (rear) The 1905 Yacht Postal Stationery saw a switch to Heller values. Set Date(s) 1905 1905 Yacht Postal Stationery Ei P18 Ei P19 Ei P20 (front) Ei P20 (rear) Ei P21 (front) Ei P21 (rear) The 1905 Yacht Postal Stationery saw a switch to Heller values. Set Date(s) 1905