This 20+4 pin PSU supply tester is a powerful tool for testing your PC's supply. This tester is compatible with ATX, BTX, and ITX motherboard configurations and will help you avoid expensive damage to your computer. This unit is capable of testing multiple connectors: both 20- and 24-pin supplies, SATA , Pentium 4 connectors, 6-pin PCI- connectors, 8-pin CPU connectors, floppy drive connectors, and standard 4-pin supply connectors. Equipped with four alarms, this tester will alert you of lower or higher P.G. values, lower voltage, over voltage, and no voltage. Its robust design is made to last and is Perfect for tech enthusiasts, ambitious hobbyists, tradesmen, and anyone seeking an all-in-one supply unit tester for their personal computer. Featuring a backlit, blue LCD display, this supply tester can verify that every part of your computer supply is fully operational. It will provide you with voltage read-outs and lets out a clearly audible beep if it encounters a problem with your supply. Multiple, durable plastic ports can accommodate floppy, HDD, CDROM, SATA, 4-pin (P4), 6-pin (PCI-), and 8-pin (Dual-CPU) supply connectors. You will need to have 20-pin or 24-pin cable connected when testing any other cable. Each of these testers is specially designed with a durable plastic casing. It is reinforced to keep the internal electronics well-protected from dings and scratches that can be sustained during transport and from regular use. The multi-use supply tester can connect to most personal computers. Use it at home, the office or anywhere you have a computer. NOTE: If your supply tester produces a constant beep and the 12V2 indicates "LL," this does not indicate that your supply or the tester is defective. Instead, it means the 2nd 12-volt rail is not detected. This could be caused by two things: either you are testing a supply that does not have a 2nd 12-volt rail or you have not plugged in a connector carrying the 2nd 12-volt rail. PCI , 4-pin P4, and 8-pin motherboard connectors should all use the 2nd 12-volt rail. When plugged into the tester, the "LL" indication and beeping noise should cease. Color: Black Material: PC Weight: 82g Voltage source: 20/24 pin (ATX - Connector) Voltage test: +12V, +5V, +3.3V, +5V Stand By (SB) 12V Easily test your computer supply and avoid damage to computer equipment | No batteries required Compatible with ATX, BTX, ITX supplies Size: 4.75 inch x 2.5inch / 12.07cm x 6.35cm Package Contents: 1x Digital Supply Tester WARNING: This product is solely designed for supply output tests. Do not leave it connected to the supply while unattended. It will generate heat and could possibly damage your supply. Do not plug two connectors into the tester at the same time except as detailed above in bold. Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.