I'm trying to disassemble a Z400 case so that I can access the sheet hosting the motherboard tray. I got most screws undone except 4 of them at the four corners, circled in the following picture. They look like they are Torx screws. The smallest bit I have is a T10, which doesn't fit. Does anyone know the exact size of them? I hate to go out and buy a tool just to find it doesn't fit. Thanks!