Product size: medium size high elasticity (barrel circumference 14 - 30cm, barrel height 24 - 37cm, sole length 21 - 30cm) Packing method: OPP bag Packing size: 19x13x4cm Product weight: 133g Power supply: power supply by 3vdc battery box, 2 x No. 5 batteries (without batteries inside). Please choose the No. 5 alkaline battery powered, or the No. 5 1.5V (capacity greater than 1500mAh) rechargeable battery powered, the normal carbon battery, or the smaller capacity rechargeable battery cannot be powered and does not heat up. The heating time depends on the capacity of the battery used, the larger the capacity, the longer the heating time. 1500mAh capacity rechargeable battery is powered, if foot capacity, full charge can be used for about 2 hours. Note: It is recommended to wear thin stockings inside and heated socks so that the socks are not washed frequently. When washing by hand, be careful not to rub the wires and hot parts, do not put the plugs in water, spread them out and dry them before using them. Machine wash put the plug in your sock pocket and wash it after putting it in a laundry bag. Note: The data are all manual measurement, please allow 1 - 3cm error, due to the difference in light and display, there will be a certain color difference, depending on the physical object received.