The temperature of the water is very important and is the thing which makes them reset, if it is not constantly boiling then they will fail to reset. Available in Yellow, Green, Red, Clear, Blue and Pink.
eBay
Stainless Steel Vaccum Cup Soup Lunch Box Storage Stackable Warmer Food Thermal Jar Insulated Soup Thermos Containers Cooler
Aliexpress UK
Do not microwave - only boil in a suitable saucepan using plenty of clean water. Allergy Relief. BURN HAZARD - burns can be caused even at low temperatures. Gel - non-toxic sodium acetate and water.
eBay
Stainless Steel Electric Heated Lunch Box 220V 12V 110V Home Work Picnic Car EU US Plug Food Heating Warmer Container Leakproof
Aliexpress UK
Image is only for illustrations. WARNINGS DO NOT USE IN THE MICROWAVE. The liquid content can cause skin or eye infection. If the liquid is swallowed drink water to dilute and consult doctor if necessary.
eBay
5Pcs Universal Microwave Oven Mica Plate 116x65mm Mica Sheet For Midea Microwave Oven Toaster Hair Dryer Warmer
Aliexpress UK
To use this product - 1. The contents now crystallises and heat up automatically for use. The crystalline contents are liquified again. Allow the pad to cool down. Do not eat the contents. Do not heat up in a microwave oven.
eBay
Sourdough Starter Warmer Wrap Adjustable Dough Jar Heating Wrap Foldable Sour Dough Warming Mat for Kitchen Baking Fermentation
Aliexpress UK
The temperature of the water is very important and is the thing which makes them reset, if it is not constantly boiling then they will fail to reset. Round: 9 x 9 cm. BUY 3 GET 1 FREE (ADD 4 TO BASKET TO QUALIFY -. ).
eBay
Chocolate Fondue Mug Ceramic Melting Cup with Fork Cheese Caramel Warmer Cup Heating Tea Light Melt Pot Valentine's Day Gifts
Aliexpress UK
Around 45 minutes of warmth. Gel - non toxic sodium acetate and water. Pouch - PVC (latex free).
eBay
Thickened Plastic Lunch Box, Food Warmer, Big Capacity, Container for Family Party Design, 2 L, 2.5 L, 3L, 3Pcs Set
Aliexpress UK
Warm them up and pop in your pockets before going out, perfect for dog walks or the school run and safe for all the use. Made with cotton and filled with wheat Eco friendly Size 10cm x 10cm. PICK UP OPTION.
eBay
4/8Pcs Chafer Pan Buffet Tray with Lid Chafing Trays Rectangular Chafing Dish Dish Warmer Pan Tray Chafer
Aliexpress UK
Introducing a flexible way to stay warm on your schedule. Each pair provides up to 8 hours of total heat, but you decide when to use it. It's a practical solution for your daily routines. Simple, Convenient, and Ready to Go Getting started is effortless.
eBay
130ml Chocolate Fondue Mug Melting Cups Hot Pot Ceramic Melted Cups Butter Warmer Heating Tea Light Melt Pot for Candy Chocolate
Aliexpress UK