Canal Zone, Dec. 12, 1904, 5c blue Map stamp (#12 with #9 pair, #16 and #17) tied by target killers on legal size Official Business REGISTERED cover with "CULEBRA, CANAL ZONE. / APR 11 1906 / REGISTERED." handstamp (Rg-1) and Cristobal Registry Exchange Label handstamp (RgXL-3) to United States. Backstamps include "CRISTOBAL, C. Z. / APR 12 1906 / REG DIV. REC'D" (RgRc-1) and New York (4-19) Registry Division backstamps. EARLIEST RECORDED USE OF #16. Light vertical cover crease away from everything. #16 with torn corner. Excellent 4-color Franking! Scarce & Attractive Registered cover. Important Postal History.