Teaser trailers are made usually by a montage of shots. Trailers consist of a series selected shots from the film being advertised. Since the purpose of the trailer is to attract an audience to the film, these excerpts are usually drawn from the most exciting, funny, or otherwise noteworthy parts of the film but in abbreviated form and usually without producing spoilers. For this purpose the scenes are not necessarily in the order in which they appear in the film. A trailer has to achieve that in less than 2 minutes and 30 seconds, the maximum length allowed by the MPAA. Each studio or distributor is allowed to exceed this time limit once a year, if they feel it is necessary for a particular film.