handheld gaming device, Steam Deck, SD card, high-speed, UHS-I, UHS-II, V30, V60, V90, fast read speed, quick write speed, seamless gameplay, expandable storage, microSDXC, microSDHC, durable, reliable, efficient data transfer, gaming on-the-go, portable, enhanced performance, smooth loading, high-capacity, 4K video recording, A1, A2 performance class, heat resistance, waterproof, shockproof, X-ray proof, solid-state, no moving parts, energy-efficient, plug-and-play.