I love the feel of a boiled wool slipper, and these are superior to ones I've owned in the past.  These have a sturdy sole, and I have been able to walk around outdoors in them without a problem; however, I don't know if they are actually water proof.  They are fine on slick floors, because of the silicone buttons on the sole - so no danger of slipping.  They run really small, however;  I ordered size 38 because I wear a 7 1/2 M, but they were quite short and very tight over the instep (I have that problem a lot), so I ordered 2 sizes up -  a size 40;  they're a little long but quite comfortable.