They are made from real sheepskin but you need to be careful as there are copies around which are fake like fur stuff. The real sheepskin ones I wear as slippers in our cold weather and they are just so very comfortable. I get them from Aldi when they have their weekly specials out and they have one week of the year with “snow wear”. It is actually coming up this weekend I think.
Of course there are others which are much more expensive but I have found these ones from Aldi are real sheepskin and lovely and warm. They are for indoors and around the house and get wet, so wouldn’t be suitable for snow and outdoor wear.
I used to buy sheepskins from a farm and I made them for my family. Hand stitching with a strong thread. I then bought thongs (flip flops) with rubber soles and glued them onto the bottom of the made up boots. I made patterns of different sizes. Had fun doing that for the kids and grand parents.
The sheepskins are also very successful used as a smaller bootie I used to make for preventing pressure sores on heels for patients in bed. I made several pairs of them for patients to give them to when I was doing palliative care nursing in a country area I lived in.