Tecnifibre 4S (formerly Black Code 4S) in 1.25mm is a square-profile co-polyester monofilament built for big hitters who want massive spin. Its sharp-edged square cross-section grips the ball for high, heavy topspin, while Thermocore Technology softens the structure for better comfort and impressive tension maintenance. This is a 200m reel. • 200m reel, black • Gauge 17 / 1.25mm, square cross-section for spin • Co-polyester monofilament with Thermocore Technology • Best for strong players and rackets over 300g