Gamma Ocho TNT 17/1.25 String Set is the first solid core, synthetic gut string that combines the OCHO’s unique octagonal shape  with the dynamic elasticity of our TNT technology. The all court player will benefit from the OCHO TNT’s greater spin and livelier response.  This string is perfect for the synthetic gut player looking for the spin and control of a polyester string, but who still desires the power and feel of a solid core synthetic.