Wilson's Duo Feel is a hybrid string that blends NXT with Luxilon Element for excellent shock absorption and less string bed vibration. For ideal playability, reduce tension on Luxilon Element at least 10%. Either string can be installed in the mains for superior feel and performance. Blend of NXT & Luxilon Element Ultimate touch and feel Reduce tension on Luxilon Element at least 10% for ideal playability Racket String Category: Comfort, Hybrid String Gauge: 16 L (1.25mm), 16 G (1.30 mm) String Material: Polymer, PU String Type: Hybrid