There are two main types of pretzels—hard and soft (soft being the older of the two forms). Soft pretzels are usually sold hot, sprinkled with coarse salt, and served with mustard. Pretzels are traditionally freely seasoned with salt, but low-sodium and salt-free varieties are available. They come in a wide range of shapes and sizes, from the traditional knots, to rods, sticks, rings, and bite-sized nuggets. Whole-grain varieties are also available; look for whole-grain rye pretzels.