The tecnifibre black code string is a flexible and pliable string that allows the ball to dwell on the strings for longer and create extra spin and control this unique string is made from third generation polyester with a pentagonal cross section and a co polyester core for ultimate durability making this string a fantastic functional and hard wearing string for all your needsa 200m reel will typically restring 18 20 rackets and can offer a saving of 20 50 compared to buying single sets