Many colleges and universities require not only the SAT or ACT for admissions, but also one or more Subject Tests. May is the ideal time to take the SAT Subject Tests since they correspond very closely to AP Exams, which are also administered in early May. As such, students can choose whichever AP subject they are strongest in—US History, Chemistry, Spanish, etc.—and be ready for the equivalent Subject Test with little additional preparation.
Nearly every school that requires Subject Tests requires math to be one of the subjects. Counter-intuitively, the Level 2 test is easier to score well on than the Level 1 test. Additionally, schools frown upon students who have completed high-level math courses and still take the Level 1 test. As such, the Math Level 2 test will be the appropriate test for most students.
A common misconception is that preparation for the math section of the SAT reasoning test (the "regular" SAT) is beneficial for the Math Level 2 Subject Test. In actuality, the Math Level 2 Subject Test is nothing at all like the Math section of the SAT. First, there are a variety of topics that are on the Subject Test that do not appear on the SAT reasoning test: trigonometry, imaginary numbers, and conic sections, just to name a few. Second, in the areas that that do overlap, like functions and probability, the questions on the Subject Test are much more sophisticated. Thankfully, though, the third big difference is an advantage, not a disadvantage. The Subject Test is more predictable and therefore more coachable. Students who are very strong in high school math have a very good chance of scoring over 700 with 9 - 12 hours of prep. The same cannot be said about the Math section of the SAT reasoning test, which requires a completely different approach from what has brought them success in math class.
This is a high-level class appropriate only for students who have completed or are currently enrolled in Pre-Calculus.