Type 904 dive tender is a class of Chinese dive tender designed the People’s Republic of China (PRC) for the People's Liberation Army Navy (PLAN), and the late models Type 904I and Type 904II have received the NATO reporting name Yanqian,(研潜 in Chinese), meaning Research Diving. In addition to perform diving support missions, Type 904 I and II ships are also general purpose research vessels (AGE)frequently tasked to perform various scientific research works.