Have a bike with an older-style threaded (quill-style) headset, but want to take advantage of the technology and performance of modern stems and handlebars? Then you need the Profile Design Threadless Headset Converter is for you. Capable of converting both 1" threaded to 1-1/8" threadless and 1-1/8" threaded to 1-1/8" threadless, this is a simple solution to upgrade nearly any older bike.