The EC34/28.6 | EC44/30 headset is designed to fit frames with tapered head tubes and can accommodate straight and tapered fork steerers with the appropriate crown race. The “EC” stands for “External Cup” meaning the section of the cup that houses the bearing sits outside the frame’s head tube and the “34”/”44” (top/bottom) stands for the diameter of the “skirt” that presses into the frame.
