[For soft tennis] Super engineered plastic "PEEK resin" strings boasting the highest mechanical characteristics. High surface hardness and excellent wear resistance. The tension is stiff and sharp. The natural color of PEEK resin itself does not contain color batches (color powder). Recommended for stock and co-purchase 10 pack is a quantity discount. Durable, sensitive feel Compatible with official battles "Japan Soft Tennis Federation" official competition regulations, and can be used in official battles. Rest assured. "
Please read the included instructions carefully and use safely