The mouthpiece of a clarinet includes a small strip of wood called a reed that a player attaches in order to make music. When the player blows through the mouthpiece, the reed vibrates, producing sound. Some reeds vibrate more easily than others, so the choice of reed affects play.
Before You Buy
Clarinet reeds are usually made of cane and are manufactured in different strengths, with the higher strengths being more resistant to vibration. The beginning clarinetist will find it hard to produce a good sound with a more resistant reed. Instead, the tone will sound too airy. This is because a beginner still has to develop his embouchure, which means how he controls his facial muscles and the position of his mouth and lips. So as a beginner, use a lesser-strength reed.
The strength of a reed is printed on it. They come in strengths of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 and 5, but even though the ratings are consistent within a brand, they are not necessarily so between brands. Thus a 2 strength in one brand might be equivalent to a 2.5 or 3 in another brand. Depending on the brand, you might try a 2 or 2.5 strength. Ask your music teacher for advice.
After You Buy
Reeds have to be broken in to be the most useful. You don't want to use a new reed in a performance. Reeds also have to be moisted before use. Clarinet players usually just sucks on reeds before attaching them, but there are reeds of manmade material that don't require it. These are more consistent in their strength ratings, but also cost more.
Reeds have a life of about three months with regular use. If they split or get chipped, or of they look fine but are becoming difficult to use, they need to be replaced. If you find yourself wearing out your reed too quickly, it means you're ready for a higher strength. As embouchure develops, it's important to switch to the higher strengths in order to play the clarinet's upper register.