These are a nice pair of socks that are lighter than the Phd outdoor crew socks. Very comfortable for every day wear but not as much cushion as I like when I'm hiking.These socks are excellent. A little pricey for a single set of socks but well worth it. I now have several sets, not just for hiking but for day to day use as well. Super comfortable.Added photo of size chart from product just received.These socks are simply great. I bought 3 pr to replace those i bought over 5 yrs ago and are just now getting down to threads on the heels.On weekends in particular im always wearing these. I have chronically cold feet and if i dont manage sweat im miserable. I only wear merino wool socks (diff types for work and working in yard etc on weekends). I wear these in work shoes when im on my feet constantly like for an entire day. They take an absolute beating.These are just thick enough in the right places and thin across the top. I really dislike those "hiking socks" that feel like youre walking around with sleeping bags on your feet. And these are just the right snugness by way of the blend etc. They hug the foot perfectly. I was worried i would not find the same type but took a shot from the picture and color (chestnut). I put a pair on as soon as they arrived and all i can say is... "footgasm". May buy some extras in case they ever get discontinued.I have been using Smartwool socks for probably 20 years now since I bought a couple pair along with a pair of Vasque hiking boots at a Hudson Trail Outfitters store. I like them so much I usually would buy several pair every few years in stores. The last bunch I bought was in October 2012 and I got ten pair from Amazon. Those were, as usual, great products but eventually I wear out the material right at my achilles tendon area. Those are still good for around the house during the winter.I bought four new pair recently. As others have observed, and I was aware of from other reviews, these are not the same quality as the product a few years ago and I probably won't be buying more. I noticed immediately that the socks felt rougher, the top band was a bit different in design, and it looked like the material inside the sock was not as densely woven and there were areas where the wool was coming off the socks easily. . Although they look mostly the same and feel good to wear, it looks like some costs have been cut in production. I have switched over to buying Darn Tough Full Cushion hiker socks. They are more expensive, grip the foot a bit more snugly, but give the appearance of being better manufactured. Time will tell if they last.These seem like fine socks, and if they're the same quality as other Smartwool products I've bought and worn extensively over the past ~12 years, I'm sure they'll be great on the rare occasion I'll actually wear them. I generally prefer thin socks, both to help keep my feel cool and non-sweaty and to fit better in my shoes. These are most definitely NOT thin, and Smartwool needs to pick up a dictionary and rethink how they label their socks. These socks are pretty heavily padded, certainly not the thickest, most padded socks I have, but they're up there. And they're simply not something I'm going to typically wear, since they will be too warm and they make my feet feel cramped in my shoes. The only times I'd wear socks like this are when I'm lounging around the house on a cold day or with boots outside in the winter. And I already have plenty of other socks for those situations, so these were pretty much a waste of money.If you're looking for truly ultralight Smartwool socks, I'd recommend the Spruce Street or Anchor Line socks, though I wouldn't consider even those ultra light, but rather just light. Ultra light, at least to me, would be something like liner socks. I bought a bunch of different socks looking for something similar to the now discontinued Wigwam Airlite F6003 and, to a lesser extent, Smartwoool City Slicker socks. I've found Smartwool socks to not last as long as the Wigwams and other socks I've had in the past, presumably due to using more wool vs synthetic fibers, and so prefer the Wigwams since they feel equally as great but are more durable. The closest I found out of the ones I tried were the Spruce Street and Anchor Lines, which also seem to have more comfortable toe seams than the City Slicker socks, which was the other issue I had with them.I wear these over Coolmax liners and they are outstanding. I prefer them to Darn Tough because these don't seem as tight, so I can wear them over a liner more effectively. Also, they are warmer in my opinion. I've been using these for about 15 years... I've worn out many pairs and keep buying them! Just great socks.These socks hold up to a 10-12 hour of shift work on your feet. They are comfortable and seem to be as durable as my other Smartwool products, so I expect to get many years of use out of them.These are fine hiking socks, good at foot temperature and sweat management, and have held up well over several hundred miles on the trails. However, though I ordered, received (per the packaging), and initially had two apparently identical pairs of the socks, in the same size, one pair shrunk significantly and the other did not. Have only washed and dried them together, and therefore in the same wash conditions and for the same number of wash and dryer cycles. Slightly annoying, suggests quality control issues, and how manufacturers reliably lose a star.Fantastic feel and fit to the sock and somewhat of a revelation when they were new; definitely 5 stars as I actually looked forward to putting them on?! However, I've only worn them a handful of times and probably after a maximum of 5 days/washes I noticed that they are beginning to wear very thin on the heel. I've only worn them walking the dog, with wellies and not on an arduous trek for what they were designed.I am genuinely shocked as I wouldn't have expected this rate of wear with minimal use for a product that I originally assessed, from the numerous highly rated reviews, as a quality brand.I cannot recommend these socks and I will now be choosing an alternative brand in my search to find a quality product that meets my requirements for warm, comfortable and hard wearing sock - unfortunately, the Smartwool Medium Crew Sock does not meet this.I also have been buying these for many years and until the most recent purchase, absolutely sworn by them.Sadly the quality has changed, the percentage of wool has been reduced to a point where you are really aware of the Polyester mesh that the wool is woven into. This means that the lovely feel these socks used to have, until quite recently, has been replaced with the feel of your feet sliding around inside a synthetic mesh. A real pity, I will have to look around for an alternate combined Walking & Working boot sock, Hopefully they haven't done the same to the Trekking version, but these are a lot thicker so only really useful in winter.Alternately the PHD ones might still be OK, but sadly a lot more expensive,The distinguishing mark that highlights this detrimental design change in the HIKE sock is a light green band around the inside top of the sock.EDIT: Dropping from 3 to 2 stars.The plastic "roof" of the socks resulted in a blister for me. Why on earth did they pair a great quality sole with a terrible plastic upper section for the foot?Original review:These are not bad socks but they're not amazing either.The listing claims 70-odd % merino wool on Amazon but the actual product delivered states 63%. It's not a huge difference, but something to be aware of.The sole is thick and there are no bulky hems or joins in the sock which is great. However the top of the sock feels like some kind of plastic against your foot. It's very thin on top of the sock, you can clearly see through the sock to your feet from above which might help with airflow but because of that plastic feeling they're not amazing.It's a shame because the sole and toe is really nicely made.I have bought these socks 4 times over several years (always from amazon), and always found them great for 'casual wear'....too high a manmade content for me to use for hillwalking, at 23%. A lifetime of hillwalking taught me to avoid - or minimise - manmade material in direct contact with my feet, or suffer from heat/friction issuesHowever, this time, I see the Merino Wool content has been reduced from the advertised 74% (on here) to 65% (on the manufacturers label), the other 35% being nylon (polyamid). I have reported this error to amazon.Reviewing other Smartwool socks, I've noticed some recent reviews report similar changes in composition and performance, and some regular buyers saying their repeat buys are no longer as good/effective.I'll give these a go, but if I find a similar change, these may be my last Smartwool product.The quality is excellent, they run a little large, and the price is Fair for a quality Sock.These used to be amazing socks, worn them for years and years, I’ve literally walked all over the planet in them, but, something has changed. I’m not sure what! Either the nylon content has gone up, but, they ‘feel’ different. My feet are moving around inside them and I’ve started getting blisters.Unfortunately, I’ve moved to bridgedales, as they ‘feel’ like smart wool used to do. Heresy I know!