The Special Duties Unit (SDU; ), nicknamed the "Flying Tigers" (), is the elite tactical unit of the Hong Kong Police Force tasked with countering terrorist attacks, hostage rescue, underwater search and recovery, and tackling serious crime involving firearms. The SDU is a subdivision of the Police Tactical Unit which is part of 'A' Department (Operations & Support). The SDU is based at the Police Tactical Unit Headquarters in Fanling. History The SDU was established in 1974 by the British Hong Kong Government in response to the ever-increasing threat of international terrorism. The SDU, then consisting of ten odd members, used existing police weaponry and devised their own tactics. In early 1978, the British Special Air Service sent an advisory team to Hong Kong, which was initially to evaluate the SDU and subsequently trained two land assault teams resulting in considerable changes to SDU equipment and tactics. In 1982, the British Special Boat Service sent an advisory team to Hong Kong to establish a water assault team including training in military diving. Organisation The Special Duties Unit consists of a support group, administration group, and the action group. The action group is the core of the SDU, further categorized into the assault team and the sniper team. The SDU structure consists of the following as of 2014: Administration Group (Headquarters) which is responsible for all administrative works, as well as providing intelligence to operations Action Group Assault Teams Team A, Team B, Team C (Training of SDU officers) Sniper Team Boat Team: Provides sea transportation for the assault team, and maintains the SDU fleet of small vessels Support Group Medical Support Team: Consists of combat medics who perform operations along the assault team Transportation Team: Maintains the SDU fleet of land vehicles The SDU has five Belgian Shepherd dogs. Selection and training A volunteer for the SDU has to successfully complete an 11-day selection course known as Hell Week which is held annually that has a success rate of only 25%. After successfully completing selection, the applicant is required to complete a nine-month training course that includes weapons handling and marksmanship, tactical movement, unarmed combat, breaching, climbing and roping, chemical, biological, radiological and nuclear incidents, and combat medicine. Applications are open to women officers, with no female officers to date. Between 1974 and 2014, 383 officers had served in the SDU. Prior to 1998, the SDU selection course was 10