One of the most popular strings by Babolat, widely popular for its comfort. Babolat Xcel 12m 13016 Natural One of the most popular strings by Babolat, widely popular for its comfort. Xcel is also the string used by Babolat in prestrung versions of its top of the range rackets. This synthetic string provides the next best thing to natural gut in terms of performance. Multifilament string is made with several hundred synthetic microfibers assembled into a matrix to form the core. The twisted core gives the string more elasticity and flexibility. The central core is protected by one or several outer wraps. The main characteristics comfort, power and good tension hold. Composition Polyamide Construction Multifilament ITF, FFT, FIT, RFET certified Super Tech Felt nitrogen based pressurization for more durability. Babolat Xcel is a comfortable multifilament made with a multifilament core and two outer coatings featuring polyurethane and polyamide. Xcel is soft, comfortable, and more durable than the previous version. One of the best multifilaments on the market, players will enjoy the touch, power and feel.