The DTOKO HY-991 knee massager is designed to provide relief and relaxation for knee joint issues. It features a combination of vibration, pressure, and heating functionalities. Here's a summary of its features:

- **Massage Functions:** The massager offers vibrating massage, which is beneficial for soothing knee pain.
- **Heat Function:** It includes a heating feature, which can be helpful in relaxing muscles and improving circulation around the knee area.
- **Material and Design:** The device is made of ABS material, suggesting durability and ease of cleaning.
- **Battery:** It comes with a 2600mAh lithium battery, indicating decent battery life for sustained use.
- **Massage Modes:** It has three modes, including vibration pressure heating, vibration, and pressure, providing various options for different needs.
- **Additional Features:** The massager also has settings for time, heating, mode, strength, and red light, offering customization according to user preference.