Combining durability, comfort, and spin is no easy task, but Tecnifibre Ruff Code 17 is up for the challenge. This string undergoes a sequential series of heating steps in order to soften the structure, known as the Thermocore process. This manufacturing technique helps to decrease the amount of stiffness felt in this durable co-polyester string. Ruff Code also features a unique Bi-phase process that adds texture to the outer layer of the string, providing greater bite on the ball for additional spin.