I have been using two of these Hotties on a regular basis for several years now and they are so good that if they were ever to be discontinued, I would buy up at least half a dozen so that I would never have to do without them! You just pop them in the microwave for 2 minutes or so, depending on the wattage of your appliance - and they really will stay hot for HOURS! In fact, as long as they remain in contact with your body, they never seem to get really cold. I have often woken up after an 8 hour sleep to find them still warm, which is amazing.
I use them to ease pains in my back, legs and neck etc all year round and to keep me warm in bed in the winter months. And they are SO much better and safer than both traditional hot water bottles and the type of microwave 'hot water bottles' that are filled with gel, as traditional hot water bottles require filling with very hot water and rubber ones eventually rot; and the gel-filled ones have a nasty habit of leaking eventually! Whereas these little beauties are filled with layers of some type of fabric or perhaps even paper, soaked in plain water, and their edges are very well sealed to prevent leakage. Indeed, I accidentally overheated one of mine once and before I knew it, it had blown up like a balloon in the microwave! I quickly took it out, thinking I had ruined it. But it gradually went back down - and is still working just as well as it always did, with no leakage! Of course, I wouldn't recommend anyone trying this at home (LOL) but I think this proves just how strong they really are.
TIPS:
1) NEVER, EVER, UNDER ANY CIRCUMSTANCES PLACE THEM IN THE MICROWAVE WITHOUT THEIR COVERS! This is clearly stated on the polythene wrapper. But unfortunately some people seem to think they know better than the manufacturer and they remove the fabric cover before placing them in the microwave. THIS CAN AND WILL DAMAGE THE PAD as my own daughter found out when she tried it! So ALWAYS keep the cover on when microwaving them and they will last for years, as mine have!
2) OVER HEATING THEM WILL DAMAGE THEM! So if they do not feel hot enough when you remove them from the microwave SLIP YOUR HAND INSIDE AND FEEL THE ACTUAL PAD before deciding to heat it for longer! Because you will probably find that the pad is plenty hot enough and that the heat just needs a few seconds to penetrate up through the fabric cover.
3) If they have lost most of their heat and you want to reheat them, do NOT reheat them for the normal time unless they are stone cold, as that could overheat them and damage them! Instead, adjust the heating time according to how cold or warm they are!