Certificated: TUVISO9001:2000 , TUVISO9002 and RoHS Material: CRGO silicon steel Surface:round/oval/rectangular Gapped coreGapped cores sre manufactured according to customer specifications. Cut surfaces of these cores can be round ,oval and rectangular.The preferred gap size are 1.0mm, 1.5mm, 2.0mm,3.0mm 4.0mm,8.0mm. The small sizes such as 0.20mm to 0.80mm are also avaiable. gapped core