Totally worthless. Not only are they SUPER loud at full speed (much louder than the original) but they WILL NOT function at anything less than full speed. This means that fan speed settings are useless - it's full speed or nothing. I put my old, dying fans back in as they were quieter. These are going back.

The fan is a direct replacement, but was defective. It could not spin up to past half way and was extremely loud below half it's rated RPM. I returned it and will order a different model, cutting off and swapping out the 2 pin connector.

The fan that came installed in my Mediasonic 4-bay enclosure is so loud that I decided to try this replacement fan. But this one barely blows any air and has half the amps of the original. Returned for a refund.

Starting having a noisy fan, I was looking for a replacement option and this is one is probably the only one that would work with a Mediasonic HD enclosure as they use an uncommon connector for an 80mm x 80 mm x 20 mm fan.Did the new fan resolve the problem? Not really... The actual noise problem is not the fan but the enclosure design:1) The back cover that you screw on over the fan is actually touching the fan blades generating noise. You need to keep the screw loose and wiggle the backplate when you start noticing noise. I'm not sure if spacers were provided to go between the fan and the backplate (I may have lost them), but it will be a great idea to include them (something that you thread at the screw points between the fan and the backplate).2) You can only mount the fan one way based on the way the mounting brackets were designed on the enclosure backplate. You need to look for the screw holder that is different on the lower right corner and have the cable going next to it. So if you want to invert the airflow (or no longer deal with the fan blades brushing the backplate which would remove the issue at 1), you can't do it...