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.
H2H CMTTS267 Athletic Performance T-Shirt for Improved Performance
51 Review
Optimized Airflux Sleeve for PGA TOUR Standards
43 Review
Cimic Black Athletic Short Sleeve T-shirts 520
50 Review
Newzill Compression Calf Sleeves (20-30MmHg) For Men And Women - Ideal Alternative To Compression Socks, Perfect For Running, Shin Splints, Medical Needs, Travel, And Nursing
42 Review