When you purchase this box, it allows you to send up 5 Wusthof Trident knives up to 10 inches in length back to Wusthof for Professional Sharpening. The round trip can take up to weeks, but Wusthof pays for the return Shipping & Handling. The box comes with packaging and knife tip protectors as well as instructions for the return to Wusthof Trident.