A marathon is 26.2 grueling miles affecting your body — especially your feet. Not only is the race itself long, but the training as well. Even the most casual of marathoners will endure a tedious running schedule to prepare themselves mentally and physically.

All the pavement pounding and mile after mile logged means one very important thing — you have to make sure to keep your feet healthy. While some people training for a marathon will endure runs upward of 15-20 miles, the marathon is a whole other monster on your feet. Wearing the wrong kind of sock could lead to a flash mob of blisters on your feet.

Let’s start with the most important sock tip when it comes to marathons — never, ever, under any circumstances, wear cotton socks in your marathon. That six pack of cotton socks you got on sale at Target should never find its way onto your feet during a marathon (or during any run, really). When cotton gets wet, it stays wet. You might as well strap on a couple pails of water to your feet (okay, maybe a bit of a hyperbole there). Sure it’s the cheaper option, but a performance sock is well worth the extra bucks. You’ve put a lot of time into your preparation for the marathon; you wouldn’t want to ruin it by wearing cotton.

So now you know what not to wear; let’s discuss what you should.

Since the marathon is such a long race, there’s going to be a lot of friction (a major cause of blisters). A good option for combating the friction and thus preventing blisters is a WrightSock dual layer sock. The friction will reside between the two layers of the sock instead of affecting the bottom of your foot. A dual layer sock may sound like something really thick and uncomfortable, but it’s very lightweight and breathable.

Perhaps a thicker sock is something you’re interested in though. Thicker usually means more cushion — something I’m sure heel strikers and stompers appreciate. In a long race like the marathon, it’s not a bad idea to have more cushion to help your feet stay comfortable and be less affected by the race. A couple good options here would be Drymax Running or Feetures Originals Low Cut.

Drymax is often referred to as one of the best socks to keep feet dry — plus it has great cushioning in the heel and toe regions.

Feetures is one of the most comfortable socks you’ll ever try on and its hugging fit helps reduce friction, which reduces blisters.

There are also a couple more unique options you could go with. First, there is the Injinji performance toesock. While the idea of wearing a glove on your foot is weird, consider this: chafing and blister prevention between the toes. With your toes separated, your toes won’t rub against each other.

A second option would be a compression sock. If you frequent a lot of races, you’ve probably seen these starting to pop up more and more in the past few years. Compression socks are great for helping your blood circulation in your legs. Many people wear them for recovery after runs or races — but some like to use them during marathons as well. Brands such as CEP say wearing them can increase your performance by 5%.

A marathon is a lot of work. From preparation to execution, you’ll want your marathon experience to be as smooth as possible. In order for that to happen, you have to know your socks.