The 104-key 4 Pro is equipped with N-key rollover. To prevent fading, the keycaps are hard-coated with UV protectant, while the gold-plated switches boast a lifespan of 60 million keystrokes. Transfer music, videos, and photos with the two-port USB 3.0 hub, which is powered by a 6.5-foot cable equipped with one USB connector. Other amenities include quick-access media controls with an oversize volume dial and special-function keys, a magnetically attached 4-degree footbar (which doubles as a 13-inch ruler), an anodized aluminum top panel, and a laser-engraved aluminum bottom label.