GOSEN "UMISHIMA" is a unique technology that blends multiple materials in a monofilament for diverse string characteristics. It's named after islands on the sea, signifying the merging of different elements. The number of "islands" on the "sea" creates different characteristics. The AK Series was initially created in collaboration with and utilized by the professional tennis player, Anna Kournikova.
 
The core of AK PRO features three distinct "islands," which helps to maintain its resilience and original tension.
.
Material: Original UMISHIMA structured nylon core and wraps
Gauge: 1.31㎜ (16GA.)
Length: 240m (787FT.)
Made in Japan
 
Structure and Advantage of UMISHIMA Series