With Black Code 4S, Tecnifibre gives big hitters a durable, low-powered co-poly with MASSIVE spin potential, impressive tension maintenance and great feel (especially for a firm monofilament). Boasting a square profile and sharp edges, this string puts a very tight grip on the ball. Topspin players will be able to hit high-arching, spin-loaded balls that come down sharply and explode off the court. For this string Tecnifibre uses Thermocore Technology, a multi-stage heating technique designed to soften the structure and reduce harsh impact vibrations.This helps explain why our playtesters were so impressed with the comfort level. Players looking for a durable co-poly with phenomenal control and spin-potential should definitely give this one a serious look. Gauge: 17g/1.25mm Length: 660ft/12.2 m Composition: Co-polyester with Thermocore Technology. The item "Tecnifibre Black Code 4S Tennis Racquet String Reel 17G" is in sale since Saturday, November 5, 2016. This item is in the category "Sporting Goods\Tennis & Racquet Sports\Tennis\Strings". The seller is "tenisimon" and is located in Verdun, Quebec. This item can be shipped worldwide.