Feature: 1. Rapid heating, rising to more than 40℃ within 3-5 minutes, about 10 minutes to more than 50℃, and about 30 minutes to 60℃. 2. Constant temperature and lasting, temperature test duration up to 8 hours, the specific use time varies according to the use environment. 3. Precise temperature control, non-woven cloth strict control, the maximum insole temperature around 62℃, the average temperature around 52℃. 4. Healthy and environmental friendly, no harmful substances added or used, no need for charging, safe and healthy. 5. Including 30pcs of the package, meeting your different needs. Specification: Condition: 100% Brand New Item Type: Foot Heating Patch Quantity: 30pcs Temperature: Maximum 62℃, average 53℃ Size: Approx. 70 x 90cm / 27.6 x 35.4in Shelf Life: 3 years in unopened condition Scope of Application: Suitable for keeping feet warm Ingredients: Iron powder, carbon powder, water, vermiculite, non-woven fabric, absorbent resin, salt, etc Duration: Heating lasts for about 8 hours Usage: 1. Tear the outer packing bag and take out the self-heating insoles, no need for rubbing 2. Put the self-heating insoles into the shoes, just like the normal insoles 3. Wear the shoes in after about 5 minutes . Package List: 30 x Foot Heating Patch Note: 1. Do not use it at bedtime2. Use in bedding or with heating equipment will raise the temperature, do not use3. Avoid direct contact with skin4. If children and skin are insensitive to temperature changes, please pay special attention when using5. Pregnant women and infants are prohibited6. This product is only for external heating. Do not tear the inner core7. If the air permeability of the shoes is poor and the temperature drops, take off the shoes for a moment to let the air circulate, and then the heat will continue