Named after one of the world's deadliest predators, the new Dunlop Black Widow Tennis String provides greater durability and spin generation. These benefits are a result of the Black Widow's seven-sided copolyester string. You will now be able to load your shots with more rotation than ever before. This string is perfect for the power baseliner who uses spin to dictate points with hard, heavy groundstrokes. Due to the geometric nature of this string, durability will be slightly lower than round polyester strings, but the trade off comes back with the spin and power that can be generated. Construction: Co-polyesterColor: BlackGauge: 16G (1.31 mm) | 17G (1.26 mm) | 18G (1.21 mm)Length: 40 ft. (12.2 m)