 Like all units, this Special Mission Unit contains operational detachments as well as support detachments.Candidates must have previous training in tactics, such as CQB, sniper, counter-sniper, and source development.Foreign language skills, although highly desired, are not a prerequisite to becoming a member of the ISA, though to be a SIGINT/HUMINT operator in the field with other Special Mission Units, working clandestine operations in non-permissive environments, knowing a minimum of several languages is usually indispensable (e.g.