PCIe 4.0 5.0 x4 to U.2/U.3/E1.S/E3.S hard drive adapter card holder/housing (R27A-BK3 supports U.2 hard drives/R27BK3 supports U.3 hard drives/R27C-BK3 supports E1. S/E3. S hard drives with housing) Material: iron+copper