Case fans only spin while at full speed

Solution
Those Segotep fans are designed in a such way so that they run only at 100% and change their LED color automatically.

Then again, what else you'd expect for €19? I payed €74 to get my HUE+ & AER140 RGB combo which are proper RGB fans with controller included but there are 2x fans in the pack and not 3x fans,
specs: https://www.nzxt.com/products/aer-rgb-hue