Material:Nylon microfilament. Gauge: 21 light (.73mm). Color: Blue, orange, white, neon orange, neon yellow, power orange (black/neon orange), power green (black/neon green). Advantages: 10% thinner string for greater power. 3,000 microfilament construction for power and resiliency. Superior tension-holding at tournament level tensions. Textured surface for added control and spin. XL construction gives added strength and less string movement. BENEFITS: Usage: World class professionals and advanced amateurs. Added strength for higher tension and superior durability. Stringing tension: Up to 33 lbs (15 kgs).