Amazon.com : HEAD Sonic Pro Tennis Racket String 660' Reel - 16 Gauge Monofilament Racquet String, Black : Sports & Outdoors
Amazon.com : HEAD Sonic Pro Black Polyester Tennis String, 16g / 1.30mm (2 Sets) : Sports & Outdoors
Amazon.com : Head Velocity MLT Black Colored Multifilament - 17 Gauge - Tennis Racquet String Sets 4-Pack (4 Sets Per Order) - Best for Comfort and Power : Sports & Outdoors