"Cane Creek offers its components in a wide range of options, and its wallet-friendly 40-series provides room to create a custom headset for the frame of your choice. Made with durable, lightweight 6061 aluminum, the 40-Series IS41/28. 6 Short Cover Top is part of Cane Creek's IS, or internal, headset line, and as with all Cane Creek componentry, the IS42 can be used with any other parts from the 10, 40, and 110 series lines. Designed for straight head tubes and non-tapered steerer diameters of 1-1/8"", the IS41 comes with a steel crown race, and is built with a top stack height of 9mm, and a bottom stack height of 1mm."