The SAT II subject tests, officially called "SAT subject tests," as of 2014, are hour-long subject based tests that focus on specific topics. There are 20 SAT subject tests in English, history, foreign languages, mathematics and science.
Although many people still refer to the tests as the SAT II, in 2004 the College Board dropped the roman numerals, changing the name to the SAT subject tests. The subject tests help college applicants distinguish themselves with a more diverse portfolio. Subject tests give applicants an opportunity to showcase the subjects in which they excel. The SAT II subject tests are also sometimes used by universities as placement exams for specific programs, and they allow students to receive credit for introductory level courses.