What are the similarities and differences between a Theatrical trailer and a Teaser trailer?

A Theatrical and a Teaser trailer share similarities and difference, since being released at different times of the production cycle and due to the separate objectives and reasons behind them. I have completed this research because the teaser trailers offers an insight to our production in the early stages as well as enabling us to get feedback and a hype, both from the potential target audience. Additionally, it will develop our practical skills because of the different requirements to successful make a Teaser in comparison to the full length Theatrical trailer.