Powerline 16 Is A Unique Polymer Technology String For More Energy Return And Additional Power. Featuring The Pacific Pre-Stretch System, Tension Maintenance Is Enhanced, Allowing The String To Play Up To Its Maximum Potential For A Longer Period. Designed For The Player Seeking Power Above Everything, Powerline Will Give Players The Power And Comfort Of A Multifilament String, With The Enhanced Tension Maintenance Of A Solid Core Construction. Atp Official String