VEVOR Full Leg Massager, Air Compression Leg Massager for Foot Calf Thigh Knee, 2 Knee Heating Levels, 3 Modes & 3 Intensities, Leg Compression Massage Boots for Circulation, Swelling and Pain Relief

They're a pair.

The product description states it comes with 15-minute automatic shutdown timer, preventing excessive usage and ensuring safety. However, it does not specify if the heating pads are safe for extended use.

This is 115 VAC compatible. It has an adapter to transform the voltage, so the external voltage has no effect.