Very well made. Optimum hardness and holds wonderful. Ideal for vibrant fan to lay still. One need not always buy brand fan, so are claims also inferior fan Silent justice. Tested with a 80mm fan cheap. Bolted to housing's hear an unpleasant hum even at 5V, with these rubber pads can be heard even at 12V only the air noise. They are processed better (smoother) than the much more popular EKL Alpenföhn spaetzle.
Installation Tips:
1) cross traverse two buffer through the bores of the housing and the other two can only rest, so you can reach an optimum damping. 2) For the gums pull through use viscous liquid soap by the housing and fan holes. 3) To remove a taped screwdriver use, so you get the rubber also undamaged out again.
I am absolutely zufreiden with these rubber pads and can each friend.