A plug-in diffuser is a device that disperses essential oils or fragrance into the air, creating a pleasant aroma in a room. It typically plugs into a wall outlet and uses heat or a fan to spread the scent evenly. Many plug-in diffusers come with refillable cartridges or bottles, allowing users to easily change scents as desired. These diffusers are popular for their convenience and ease of use. They can enhance the atmosphere of a space, making it feel more inviting. Some models also include features like adjustable intensity settings and timers, providing customizable options for users.