Muscle pain massagers are powered three main ways: manual (no battery), battery-powered (typically built-in rechargeable lithium‑ion), and electric plug-in models.
Heat options are applied either with warmed pads or directed infrared heat. Herbal or fabric neck/shoulder wraps are often heated in short microwave increments or chilled in a freezer, while infrared lamps are positioned over the target area and adjusted for comfort; some heated chairs combine heat with massage functions.