We purchased these phones brand new under a year ago for our nonprofit animal shelter. However, due to our location, our internet is just not strong enough to support VOIP so we've had to go back to traditional landlines. We have seven (7) of the model: Yealink SIP-T21P E2, and one (1) each of the models: Yealink T46S and Yealink T41S. All phones include the power adapter and all work well with no missing buttons or damage. As I said we didn't even get to use them for a full year. They all have many useful features and will include the instruction manuals. You can Google the models to learn more about them.