http://www.intelligenthorsecare.co.uk/coolheat-rugs
It's very light weight and I keep putting my arms in it and all her coat is warm and dry under it even in the sideways freezing rain last night.
I bought it so I didn't have to worry about taking rugs on and off as Im only up once a day. She's a good doer so only needs something to keep her dry.
When I went up today it was filthy so I think she's enjoyed rolling in it. Will let you know how she goes in it this winter.