Type: Cable Tester and high quality.The Card is POST (Power On Self Test) card too.It could display the code by the of POST.Then you would determine system, or blank screen.You can check your computer by POST and 't have to open motherboard.LED displays and you can see code table in the manual to check your computer.Item Type: Network Repair Tool KitSuitable type:PHOENIXBIOS4.01 TO 6.0 BOIS PC AND DESKTOPAMIBIOS6.24 AWARDBIOS4.51 BOIS PC AND DESKTOPBM T20 T21 T22 T23 A21 A22 A20 DELL640 4030 etc.colour:redMaterial:Metal + PCSize: 8060mm/3.152.36in (.)LED Size: 50207mm/1.970.790.28in (.)Package Contents:1*Computer Diagnostic Card1*English ManualOnly the above package content, other are not included.Note: Light and different displays may cause the color of the item in the a little different from the real . The measurement allowed is +/- 1-3cm.