Unused on cover / entire letter -- registered to Hong Kong, bearing 1891 6c. on 8c. mauve (light stains), both cancelled by oval of bars, showing Labuan (19.6.93) and "SINGAPORE/TO HONG KONG" (25.6.93) c.d.s., curved "REGISTERED/NO" and "R" in oval h.s.; some slight age stains. Very rare and attractive. Photo