The tecnifibre duramix hd 130 string is made from the mixture of polyester 50 and polyamide 50 microfibers it has been provided with an anti abrasion coating that makes it much more resistant tecnifibre have enhanced the performance of this string by replacing standard pu with their new formula for high density pu the string is a great combination of feel control and maximum durability it has a gauge of 16l 130mm and is supplied in a reel of 660ft 200m