I know. I've never heard if them either. http://www.blazewear.com/heated-rug.html I wouldn't get one unless I could find a significant amount of research into it done. But apart from their own website there's not much in them. They do other stuff too.
Depending on the amount of heat they actually generate, I think they could be so dangerous in the wrong hands.
Over rugging is a massive problem in this country, and vets are really starting to see more and more dehydration cases and other problems associated with it. I can well imagine that certain people who have the tendency to over rug would jump at the chance to use one of these rugs thinking that they are 'keeping the horse nice and toasty'.
I agree with the other posters. Why would you need one? The only possible time would be for a severely malnourished and cold horse, just to get them warm under controlled conditions. Might be useful for a vet, say, or a rescue organisation. Apart from that, nah.
I think its designed primarily as a muscle warm up device (so supervised use), probably for those that would normally use a solarium but don't have access to one while away at shows rather than as a rug per se.
I tend to under rug rather than over. 4 out of 7 ponies in my field are not rugged at all. They all live out happily 24/7 and not skinny but not over weight. I was only thinking of warming up muscles before riding for my older boy. Wouldn't be on for long or unsupervised. It was only an idea. I came across it when I was looking at magnetic rugs. I just wondered if anyone had one. I'm still not convinced though and definitely not rushing into buying one. I like to know everything about something as well as opinions. Before I decide things.
We got one a couple of years ago, and I must admit we rarely use it.
It's not designed to be on the horse 24/7, just before ridden work to start getting the muscles warm, similar to how you'd use a massage pad I suppose. I certainly wouldn't leave it on for long periods of time, but I can't imagine that the battery would last a massive amount of time as they do need recharging after every use.
We found that it came up small and was probably more suited to lightweight types than our giant warmbloods! I think we got a Large but it was small on anything over 16.2, and wasn't the best fit on a chunky 16.1. That said, they may well have changed the sizing now as it was a while ago.
I've got the heated waistcoat as well, amazing for standing on freezing cold station platforms waiting for delayed trains.