These are an extension (and improvement) on nylon strings, which were brought out few years ago, to compensate for the lack of durability from natural gut. The classic example is Prince Synthetic Gut. The majority of factory strung rackets are strung with synthetic guts, and are a good choice for most people. They give a good mixture of power and control with a "crisp feel and sound". They do not offer much potential for spin, however, unless you go for a "textured or spin" type. They are also available in a variety of different colours. Synthetic strings are good on their own, or in combination with more durable kevlars and polyesters.
High Balance & High Sweet Spot - delivers greater power without sacrificing control. Suitable for advanced and experienced players. Inexperienced players may find it difficult to hit the sweetspot.
Medium Balance & a Centre Sweet Spot offer the right mix for intermediate to advanced players. These players play regularly and want to improve their game.
Medium High Balance & Slightly Larger Sweet Spot - a good all-around choice that can be used by players of all skill levels. Perfect for intermediate and recreational players alike.
Low Balance & Bigger Sweet Spot - for players to start, and play comfortably. The low balance and larger sweet spot also help prevent tennis elbow.