Open your mail with this distinctive modern knife inspired by prehistoric tools—“sekki” in Japanese. “I was fascinated by the beauty of the stone tools using crushed volcanic glass,” said designer Hiroki Yasuda of the obsidian implements that inspired his design. Made from PBT, a crystalline polymer, it features a faceted form that fits your hand and a sharpened tip for slicing envelopes with ease. 4.6" x 1.6" x 0.5." Made in Japan.