Zynex Medical makes and sells prescription electrotherapy devices that treat chronic and acute pain without medication. The flagship product is the NexWave, a portable, battery-powered home-use device that delivers electrical stimulation through surface electrodes to interrupt pain signals. The NexWave supports three therapy modes — interferential current, TENS, and neuromuscular electrical stimulation — in a single unit. Zynex sells exclusively in the U.S. through a direct field sales force that calls on physicians and physical therapists, who write the prescriptions required to dispense devices. Zynex then ships directly to patients and bills their insurers. Zynex also sells private-labeled rehabilitation products (braces, traction, compression therapy), which now represent roughly 30% of orders, as well as recurring consumable supplies (electrodes and batteries) that represent roughly two-thirds of total revenue. The size and productivity of the sales force is the primary driver of new order volume and revenue growth. Zynex also has a pre-revenue hospital monitoring subsidiary, Zynex Monitoring Solutions, which is developing laser-based oximetry and fluid monitoring devices, the most advanced of which — NiCO, a pulse oximeter designed to eliminate skin pigmentation bias — was pending FDA clearance as of early 2025. ZMS is funded entirely by the core pain management business.