The mach one shoulder rests are ergonomically designed to fit naturally against the curve of your chest/shoulder. This mach one is made from a high-tech double-injection mold, the main body of the rest is resilient and strong and the contact surface has leather lining and strap for comfort and grip. The attaching feet are molded out of a single piece of nylon and will not damage your instrument. Even more ergonomic than the original Mach One, the Mach One Hook hugs the shoulder even more. The idea is to continue hugging the shoulder as far as possible, creating a slight "hook" on the shoulder side of the Rest. Peter Mach's idea was to create the slimmest Rest ever. This elegant Shoulder Rest is only 5.5 mm thick! The thick unsightly foam pads have been eliminated and replaced with the best quality nubuck leather pads. This new rest fits so well, and since it does not slide off the shoulder, it almost eliminates the need for the leather pad. This Mach one is made from a high-tech double-injection mold.