Turntable needles, also known as styli, are small, pointed objects that are used to play vinyl records on a turntable. They are typically made of diamond or sapphire and are attached to the tonearm of the turntable. The needle is placed in the groove of the record and vibrates, creating sound waves that are amplified by the turntable's speakers. The stylus is an essential component of a turntable and must be replaced periodically to ensure optimal sound quality.