K-Swiss SI-18 International Heritage - Womens - White/Classic Blue/Ribbon Red : Grand Slam. The Si-18 International is an classic silhouette built for tennis. Features such as the signature D-R-Cinch lacing system and heel stability counter were designed for you to give it your all on the court. The mid-top sneaker's full leather upper is complemented by vintage branding elements, including an embroidered tongue tag that pays homage to the four host countries of tennis' most prestigious tournaments. Rich leather upper. Textile collar offers comfort. Rubber outsole offers traction and durability.