Portable neck and shoulder massager. This device, often called a "neck massager" or "shoulder massager," is designed to relieve muscle tension and pain in the neck and shoulder areas. It typically features rotating nodes that mimic the kneading and pressure techniques used in massage therapy. Some models also include a heating function to further relax muscles and improve blood circulation. These massagers are often cordless and rechargeable, allowing for convenient use at home, in the office, or while traveling