The BX²™ Edge for Surface Book is engineered to be an extension of the device, allowing for full access to the innovative features of the Surface Book while providing best-in-class protection. Co-molded from TPU/PC materials, the BX²™ Edge features Brenthaven’s Crumple Zone Corners, which absorb and dissipate the force of impact. The two-piece case is protective in both laptop and tablet modes, and includes a drop-down hinge to protect the bottom edge of the clipboard when separated from the device. Does NOT fit Surface Book with Performance Base.