Sendust/Kool Mu Cores has following features: 1.Core losses Significantly Lower than Iron Powder Cores. 2.Good DC-Bias Characteristics. 3.Cost between Pure Iron and MPP. And it mainly used for : 1.Switching Regulator Inductor 2.In-line Noise Filters 3.Paulse Transformers,Fly-back Transformers 4.PFC Chokes xxxxx We have many kinds of this items,the detail please look through our website: xxxxx we can OEM according to customer's request.