The Soviets started assisting China inside manufacturing of ROMEO submarine in 1959. The Chinese variation is recognized as the sort 033 . The Chinese Type 033 incorporated some improvements regarding original ROMEO, including sound reduced amount of at the minimum 20 dB. A complete of 84 Type 033 submarines were integrated Asia from 1962 to 1984, plus a few exported abroad. Today most of the Type 033 submarines happen resigned or preserved, with few remaining for training purposes.