I love these. After having compared many different types of compression socks, they are the only ones I wear during my 12 hour nursing shifts. I rotate five or six pairs that I have had for 2-3 years and they all look and feel as if they are brand new. I'm 5'8" 120lbs and I wear the 00A size despite that not being what the size chart advises. They are plenty long, so I'm not sure why it says I should be wearing a 00C...I imagine a girl the same weight as me at 5' would have wider calves than me, yet 00A is what is recommended for someone at that height at 120lbs. Anyways, that's just me! The 00A works well for me...they are definitely snug, as compression socks should be. The ribbing on them does occasionally start to annoy my legs at the end of my 12 hours, but they get the job done better than any others! I guess that ribbing is part of what makes them work so well!