This alarm clock produces a sunrise simulation for peaceful waking with gradually increasing light and sound. There are several settings you can personalize such as what sound you wake up to, the light brightness, and the amount of time you want it to gradually brighten. You can set up to 2 alarms with a prerecorded sound (like birds chirping) or a radio station. It also has a sunset simulation setting that starts with bright light and gradually dims, as well as a “night light” setting that produces a warm red glow with 2 taps when needed in the middle of the night. There is a USB port in the back for charging cell phones. This has been used for several years but is still working great and in wonderful condition! I’m just simplifying. Stock photo is for reference. It is the closest product available but the model I’m selling is the HF31. The description on Amazon for the HF3520 model is very comparable (no differences I am aware of).