Diadem Solstice Black 16 1.30 Tennis String Packages : The Diadem Solstice Black 16 1.30 tennis string is aggressively shaped to unleash massive spin. This co-polyester string offers a softer alternative than the Solstice with a low-friction surface and maximum bite on the ball. Star Core Technology uses a six-pointed geometric cross section that equally distributes contact between the strings, reducing friction while amplifying snapback. Simultaneously, the star shape creates a larger surface area to add more bite on the ball. If you want to swing with vicious spin, try the Diadem Solstice Black 16 1.30!