Tier One Sports Black Knight - Co-Poly Tennis String for The High Performance Player 18 gauge (1.18 mm) - 200 m reel

What makes this 6 sided co-poly string so truly special is that although, it is very soft/arm-friendliness (based on USRSA lab results), it holds tension extremely well (based on USRSA lab results), offers outstanding durability AND provides the high level player with precise depth and directional control. It is common thought to assume that the string would respond very "springy" and loses tension quickly due to its softness. Quite to the contrary, this is one of the string's strengths!
KEY FEATURES: Great directional and depth control, exceptional durability, access to spin, arm-friendly.
RECOMMENDED PLAYING LEVEL in 16 gauge: NTRP: 5.0-7.0, UTR: 9-16+ (advanced - pro level)
RECOMMENDED PLAYING LEVEL in 17 gauge and 18 gauge: : NTRP: NTRP: 3.0-5.0, UTR: 2.5-9.5 (intermediate - advanced level)
LENGTHS: Sets: 12.2mm/40ft, Reels: 200m/656ft, GAUGES: 16g (1.28mm). 17g (1.23mm), 18g (1.18mm), COLOR: Black.