Vivo Y400 12/256GB: Discover the Breathtaking Speed You Deserve is a mid-range 4G smartphone that offers a large AMOLED display, a substantial 6,000mAh battery, and robust IP68/IP69 durability ratings for its price point. Design & Durability: The phone has a slim profile (7.9mm thick) and a weight of around 196-198g, with a composite plastic back available in colors like Dynamic Green and Pearl White.