Unlock is a five-level academic skills course that combines carefully scaffolded exercises, a comprehensive approach to critical thinking and motivating video. Unlock Listening and Speaking Skills Level 4 provides 60-90 hours of classroom material. Access to the Online Workbook is provided via a code packaged with the Student's Book. Critical Thinking sections give students frameworks to formulate their own opinions and express themselves effectively in the end-of-unit academic tasks. Unique research into common learner errors (using the Cambridge English Corpus) focuses the language used in Unlock on those areas learners find most challenging.