These things are perfect for hard mud! I've ridden these things a full 10 miles and can say they're still fine. As for performance. These socks dry quickly! In fairness, you must have special shoes that shed water and dirt. But they protected my foot from mud which was very nice. Of course, you shouldn't expect socks to stop EVERY bit of dirt, but they did for me. As for the size, if you have big feet like mine (12.5) then get the big ones. If you have a shoe size 9 or 10 I assume a large or medium size will do, but for the most part the large size is your safest bet as these are really small socks. I bet my big ones fit smaller feet too. All in all, this is what you need when working in tough dirt.
Men'S Long Sleeve Polo Shirt - Slim Fit, Stretchy, Breathable Collar
43 Review
Men'S Regular Fit Short-Sleeve Dress Shirts By Allsense - Look Stylish And Professional!
41 Review
Van Heusen Traveler Stretch Men's Shirt
47 Review
H2H Mens Casual Slim Fit Short Sleeve T-Shirts Cotton Blended Soft Lightweight V-Neck/Crew-Neck
46 Review