The squash racket is an extension of your arm, so it’s an essential part of your equipment. If you are a beginner, then the rackets need to have a larger head to encourage the player. Also, make sure the racket is not very heavy. Otherwise, you might lose the balance of it.
Squash rackets with a core have a wider string pattern and a larger hitting area. This shape is more tolerant of off-center hits. There are different types of squash strings and different tensions.
Better quality strings will provide better feel and spin. Concerning durability, everything depends on the gauge: the thinner the string, the faster it will tend to break but the better the feel.
Many people think that the higher the tension of a racket, the more power it produces. This is totally false, it is the opposite! Squash racquets all have the same grip size. It is possible to increase the grip size by changing the grip or adding overgrips.