Twelve South (12-1105) BookArc for MacBook Pro BookArc helps you free up valuable real estate on your desk, giving you a cleaner, less cluttered, Zen-like workspace To ensure the perfect fit, BookArc includes two different sized scratch-free, silicone cushions. These inserts gently grip the various MacBook and MacBook Pro models and ensures the perfect fit right out of the box. Cushions are super easy to install and remove making it easy for BookArc to switch from one MacBook model to another.