Built with durable, SGCC steel, the VSK4000B-U3/U2 is a tough case meant to last for several builds without fail. The VSK4000B-U3/U2 also meets Thermally Advantaged Chassis (TAC) 2.0 guidelines & is equipped with one USB (Universal Serial Bus) 3.0 & one USB (Universal Serial Bus) 2.0 port, nine drive bays, & seven expansion slots.