brand new and high quality Features: Insole built-in activated caron, iron powder, non-slip paper etc. Long-term effect and durable, keep warm ans keep healthy. Promote blood circulation, increase metabolism, immunity enhancement. Ease pain, relieve fatigue. Wear comfortable, does not affect work, study and life. Without using any energy, reliable and eco-friendly. Self-heating product, no external power and heat. Specification: Continuous heating time: Max. 10 hours Average temperature: About 40 Material: activated caron, iron powder, non-slip paper etc. Color: As picture shown Optional Size: app. S / L 23 x 7cm / 9.05 x 2.75in 25 x 8cm / 9.84 x 3.14in Quantity: 10pair(20pcs) Note: Transition: 1cm=10mm=0.39inch No retail package. Please allow 1-2cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you Package includes: 10pair(20pcs) x Foot Heater Pad(other accessories demo in the picture is not included.)