The center/institution conducting the oral coaching classes chooses the type of material that they would use for imparting training in the prescribed syllabus. They may also opt to use the study material which is used for students taking up postal coaching.
If the same material used in postal coaching is not provided by the institutes/coaching centers for the students undergoing oral coaching classes, it is advisable to acquire a set of it. This postal material would give a clear idea of the depth and width of the subject that the student is supposed to be thorough with.