Tecnifibre 4S (formerly Black Code 4S) is a spin oriented and durable tennis string that lets you hit hard and generate your own power with big strokes. 4S has a square profile that bites into the ball really well for great spin, especially for players that  have good technique to generate topspin. Impressive from right off the stringer to the point it breaks, Tecnifibre 4S tennis string is a great choice for players that want to generate spin and maintain some durability with a shaped string.

Tecnifibre 4S 18/1.20 Tennis String (Black) Specs:

• Gauge: 18
• Diameter: 1.20 mm.
• Construction: Monofilament
• Composition: Co-Polyester
• Shape: Square
• Colour: Black
• Length:  40 ft. / 12 m.
• Made in France
• Product Code: 04G4S120XB