Very big, good price
I chose this watercooling because the manual of my bequiet case said that the 420 mm is accepted. However, it is not mountable in the top position of the case, because it is very thick (good point because thermal inertia and bad point because bulky)
The small pump fan allows ventilation of the motherboard's power supply stages. This is functional.
Tested with an I-9 11900k at high load, reached 96°C max in a dive. (on an SDK unreal engine 4.21) (mounted in front position)
As for the noise, at 100% it is the noise of your childhood fridges. Nothing too traumatic but still noisy.