Hybrid is made by combining two different strings into the stringbed, one is used in the main and the other in the cross. By selecting hybrid, players can combine the characteristics of different strings like comfort, durability, liveliness, control and power.
The most common hybrid among tour players is a polyester in the mains and multi-filament or synthetic in the cross. Putting polyester string in the main will give good spin and control whereas a softer string like multifilament or synthetic will soften the string bed and decrease the stiffness that can be found in a full bed of polyester.
By reversing the hybrid combination, having soft strings in the mains and polyester in the cross, the result is a comfort setup with better feel. Players who are not frequent string breaker and who prefer softer feel will like this setup.
Hybrid stringing is used by some of the top ATP Pros including Roger Federer, Novak Djokovic, Andy Murray, Marin Cilic, Serena Williams, Maria Sharapova.