Racquets are the most technical pieces of equipment used in tennis. Over time, their construction has gone from wood to metal alloy to carbon-fiber composites. Because they're designed for the playing techniques and physical needs of an individual player, the marketplace offers countless custom options. The two most important racquet qualities for most players are control and power. Advanced players are more interested in control since they possess more developed power skills. Racquets come in a wide variety of sizes and weights. A lightweight racquet with a heavy head is harder on a player's arm than a heavier racquet with a light head. The spot on the racquet that best hits the ball is called its "sweet spot." Less energy is lost and more control is generated when the ball connects to the sweet spot. Large-headed racquets have bigger sweet spots, which is one reason they're preferred by beginners.
The importance of racquet string can't be underestimated; its task is to connect with the ball and send it back across the net with precision. The type of string put on a racquet can effect a player's wrist and arm---either protecting against or causing fatigue. String type also has an impact on racquet power, control and spin. The most widely-used string types include natural gut, which is widely considered the best option for power, control and injury prevention; synthetic string with a solid core, which gives a racquet inexpensive control and playability; and synthetic string with multifilament construction, which is an economical version of natural gut string. All racquets have a recommended string tension range. Adjusting strings to the low end of the range will result in long shots, while the high end of the range results in short shots. According to doIttennis.com, "the wrong string type and inappropriate tension can make a $250 racket feel like a wooden club even to the most skilled of players."
In adherence to the strict regulations of tennis balls' physical characteristics, the ITF has approved approximately 200 brands for play. The industry has come up with numerous different tennis balls that are meant to interact with the court on which they're used. Since distinct court materials play "fast" or "slow," balls are chosen based on court type. Type 2 balls are standard, useable on any type of court and in any location. Type 1 balls are harder, faster and newer to the game; they're reserved for courts made of materials known to slow ball speed. Type 3 balls are slightly larger and slower, and utilized on courts known to speed up the game. Tennis balls made for specific use on high-altitude courts were introduced to the game in 1989.