Very powerful blowers! Not silent due to massive amounts of air they are moving. Unfortunately, on default Marlin firmware settings hey won't spin below 100% fan speed. Make sure to uncomment #define FAN_SOFT_PWM in Configuration.h With this setting enabled I can run them nearly silent at 85% speed with decent cooling. For bridging I set them to 100% speed in Cura, which is noisy, but crazy efficient. You can also tune usable fan speed range with #define SOFT_PWM_SCALE, if needed.
It works, but it seems like it's not new... There is scratches along the case and sticker on the back was peeled off and sticked back on. Works just fine though, and don't give vibrations.