Brenthaven BX2 Edge for Surface Pro 4,Smoke Gray - 2662 Co-molded construction uses high-grade polycarbonate and TPU that is UV-stable, crack resistant, and flexible Crumple Zone corners and proprietary BX2 Xtreme Foam absorb and dissipate energy from impact Tested from six feet to exceed military drop standard MIL-STD-810-G Integrated side recess for Surface Pen and optional tether to prevent loss of Surface Pen 100% Lifetime Guarantee