Hybrid Tennis Strings
All the various types of tennis strings have different characteristics that produce different combinations of power, durability, comfort and spin.
Instead of just using one type of string on both the mains and crosses, players have begun stringing rackets with two different types of strings, one for the mains and one for the crosses. This type of stringing is called hybrid stringing.
The advantage of hybrid stringing is that players can gain the benefit of different types of strings to increase the overall playability of the rackets.
In a typical tennis racquet, it's almost always a main string that breaks. The reason for this is that the main strings move a lot more than the cross strings. This causes the cross strings to cut into the main strings, causing notches and eventually breakage.
So, in hybrid strings, a durable string such as a polyester tennis string or a kevlar tennis string is usually used as the main string. This provides increased durablity.
For the cross strings, usually synthetic strings or natural gut strings are used. These strings provide comfort and feel.
So, a hybrid string job provides both good feel and increased durablity.
There is an almost infinite number of possible string combinations. As you can create highly individual combos, hybrid strings are becoming more and more popular. There are also some pre-packaged hybrids available from the major string brands.