The document analyzes four different radio trailers that were made to advertise documentaries. It summarizes the key features of each trailer, including length, use of voxpops, narration, music and sound effects. Overall, the document finds that effective radio trailers are short, around 30-60 seconds, include upbeat music and voxpops from the documentary, and end by providing airing details for the documentary. Through reviewing existing trailers, the researchers identified best practices to incorporate into their own radio trailer.