100% waterproof/breathable boot-liners.
For use in any boot or shoe for warm, dry feet when needed. Will fold into a pocket when not required.

Could be worn as a tent boot.
They are very thin material but will take up some room in your footwear.
Suitable for many uses: walking, hiking, military, dog-walking, river crossing, flood, etc. Very tough and durable.

Some stocks of 'small' are also available in calf-length. These are very narrow width fittings and are available at a discounted price.