$14-18 Per Set
16, 17, 18 Gauges
high Stiffness
15+ Min Age

Performance Ratings

power 5/10
spin 10/10
control 10/10
comfort 5/10
durability 8/10
tension Maintenance 7/10

Lab Test Data

Stiffness 209 lbs/in

Junior Player Guide

For Parents
Arm Friendliness Low
Cost Effectiveness Great value

Recommended Level

advancedelite

Tension for Juniors

44-48 lbs for juniors. String low due to stiffness.

Gauge Recommendation

17 (1.25mm) for maximum spin.

Overview

Black Code 4S is Tecnifibre's maximum spin and control polyester with a square shape and four grippy edges. Lab tested stiffness of 209 lb/in makes it quite stiff. "This string's most undeniable characteristic was control" - it enabled playtesters to execute their most powerful strokes without fear of overhitting. The ability to take massive upward cuts combined with the four grippy edges was "a recipe for massive spin." Low powered but provides excellent bite on the ball.

Best For

  • Maximum spin seekers
  • Advanced players with full swings
  • Control-obsessed baseliners
  • Those who generate their own power

Not Ideal For

  • Beginners or intermediates
  • Players with arm issues
  • Power seekers
  • Comfort seekers

Pros

  • + Maximum spin from square 4-edge design
  • + Exceptional control - can swing freely
  • + Great for aggressive topspin
  • + Good durability
  • + Predictable response

Cons

  • Very stiff (209 lb/in)
  • Low power
  • Not arm-friendly
  • Requires full swings to access benefits
  • Should be used in hybrids for most players

Specifications

Type polyester
Construction Square-shaped co-polyester with four spin edges
Gauges 16, 17, 18
Colors Black
Set Price $14-$18
Reel Price $150-$180

Used By

Various ATP Challenger and college players

Hybrid Setup Ideas

  • Natural gut or multifilament mains + Black Code 4S crosses
  • Should be hybridized for most players

Stringer Notes

Stiff string - recommend stringing low and using in hybrids. Great as crosses with soft mains.

Break-in Period

1-2 hours.

When to Replace

Every 12-15 hours when spin drops.

Sources

Data verified January 2025

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