North Vietnam, Ocean Crabs, August 19th, 1965, Michel Nr. 387-392; Six stamps with the nominals of 12 xu (four stamps), 20 xu and 50 xu were issued in perforated 11.0 and imperforate.
Here is the perforated set.
Here is the mint imperforate set:
Registered letter mailed to Klewitz in August 1968 featuring the entire perforated set. The overall postage of 1.18 Dong was slightly above the required postage for a standard registered letter to West Germany (1.10 Dong Tariff)
Registration Nr. 101140