The German-developed NB-BlackSilentPro fans combine the the frame technology of the original NoiseBlocker-BlackSilentFan with the NB-EKA Plus II Drive electronics and the NB-NanoSLI bearings of the high-end NoiseBlocker-Multiframe series. The end result is a reliable fan that boasts high performance and ultra silent operation.The NB-BlackSilentPro fans also come with variable cable management system which includes two sleeved fan connector cables: 200mm and 500mm. Use one, the other, or both depending on the cable length you need for your application.The newly developed mounting hardware includes the NB-Silentframe with the complementary silicon gasket and long screws paired with knurled nuts for tool-free assembly.Noteable features include: Low start voltage. Long 6-year manufacturer"s warranty. Glass fiber-reinforced chassisAnti-dust polycarbonate rotor. Developed in conjuction with direct collaboration with the community.