These boots are great.Bought them from Amazon US as UK one doesn't offer them (nowhere in the UK does to be fair) but so pleased I did.The great thing for me is, whilst they are TOASTY warm even with a thin pair of socks on (may have to bulk up in severe cold) is that if I leave the laces tied loose(ish) then I can slip these on and off with ease and don't have to worry about them falling off my feet as they aren't too sloppy (of course I would tighten them if I was going to be hiking miles or hunting in them) but for walking the dog or popping outside it's handy.Had them over 2 years now and the construction has held up well, as has their waterproofing and the grip is fab in the snow and mud alike. I bought a US ten which is a UK 9 (my size) and on our coldest days have worn a coolmax 'thin' sock with a 'thick' bridgedale summit (which has been too warm to be honest) but if you wanted more layers on I suggest you go up a size, as whilst it's not tight for me with the mix of 2 socks, it would be uncomfortable to have anything thicker I think.Taking my Jeep wrangler up to the Arctic on an expedition shortly hopefully (if not then it will be either the Alps, Pyrenees or Corsica) however if I do go I will post again if I have any issues, but think these will be perfect, however BE AWARE...... they take a little getting use to if your driving in them (see paragraph below).The only thing I should perhaps mention (but by no means is this a criticism or a negative) is they can seem little bit Nemesis/Battlefield Earth on your feet and this may take a couple of wears to acclimatise to, however not to the point where you look silly (they are just a tad bigger all round than a normal boot, due to the insulation I guess).When these give up the ghost I will be purchasing the same or an equivalent pair by Baffin.Seller was great too with swift delivery that if I remember rightly was free (even across the pond).