Core Milled offers numerous fashion-driven looks for Spring/Summer. The new style 3-Eye Shoe comes with duotone lacing and a sturdy sole; the Servo Lux leather offers a worn-in look that is achieved by pre-treating or 'milling' the footwear. This creates a deliberately scuffed and worn look. This also works well on the Double Monk Strap Shoe. Double Monk-Strap Shoe. Rugged Servo Lux, a smooth leather which is designed to soften over time. Double buckle fastening. Goodyear-welted, the upper and sole are heat-sealed and sewn together. Dr. Martens air-cushioned sole.