Cross country skiing requires different types of gear and supplies. From skis to bindings, cross country skiing has its own industry. Ski wax is also something that cross country skiing has its mark on, and kick wax describes a variety of waxes that are specific to cross country. Kick wax comes in a couple of variations, ‘hard' or ‘klister'.
Klister ski wax is a semi-liquid wax that typically comes in what looks like a tube of toothpaste. This stuff is extra-sticky so be careful when using it to not let it get everywhere. It is difficult to apply and is not for the beginning skier. Hard ski wax is a lot easier to handle and apply. It is a more tar-like substance that comes in a can and is best used for fresh powder and below freezing temperatures. If this is your typical skiing condition, use hard ski wax for your cross country skis.
The main advantage of kick waxing is that it provides additional friction to skiers who need to propel themselves through rugged terrain. This is what makes it so great for cross country skiing where a skier will often need to accelerate when nature and the elements say they shouldn't. If you are a cross country skier, learn more about kick ski wax before you hit the trail.