The socks are a pair, and each one needs its own device, which is why this pack has two M devices rather than one. Together they cover both feet and ankles at the same time.

The M runs on microcurrent - imperceptible, no muscle contraction, up to 10 hours at a time - so the socks can be worn around the house rather than sitting still for a session. The Perfect Conductor spray helps if the sensation feels uneven, which is more likely on dry skin than on the hands.

The socks are the way to treat the feet with an M, since the Foot Pads aren't recommended for this device.