C-Type Cores are similar to tape wound toroids in that they are made by winding a long strip of electrical steels of desired width and thickness onto a mandrel. They differ from tape wound toroids in two characteristics: it is rectangular with rounded corners, and the wound core is cut in half to form two C shaped mating pieces. (One could argue that two U shapes are formed.) The mating surfaces are polished to minimize air gap between the two halves. Further reduction in the gap may be achieved by cutting the core at an angle. One C core set (or 2 C core halves) can replace a U-U or U-I laminated structure. Two sets of C cores (or 4 C core halves) can replace a E-E or a E-I laminated structure. C cores can take full advantage of grain orientation while their laminated counterparts only take about 60% to 80%. Because of this, C core performance is better than that of laminated stacks. The rounded corners also reduce the weight.