In the education systems of England, Northern Ireland, Wales, Jamaica, Trinidad and Tobago, and some other Commonwealth countries, sixth form represents the final two years of secondary education, ages 16 to 18. It is the final stage in British secondary schools, and students typically prepare for their A-level (or equivalent) examinations. Sixth form can be attached to schools and provide students with the opportunity to stay under one roof from Year 7 to Year 13 (or to join at Year 12) or independent sixth form colleges. A school sixth form will prepare 16-18 years olds for university entrance through A-levels, IB, Highers, or Pre U, and some also prepare pupils for both BTECS and apprenticeships. Sixth form is not compulsory, but it is a preferable choice for students wishing to continue in academic studies leading to university level.