Features revolutionary design - allows quicker, easier installation without the removal of the rocker covers. .4375” diameter Chromoly steel. Threaded adjuster screws into the pushrod until the threads disengage and the adjuster simply slides into the pushrod, making installation or removal a snap. Once the pushrod is installed and adjusted, the lock nut prevents the adjuster from moving. Ball ends of pushrods are drilled so oil can flow through pushrods. Made in the U.S.A.. Twin Cam and XL applications will require aftermarket pushrod tubes that allow access to adjusters (unless otherwise noted).. S&S Quickee pushrods are designed especially for use with Evolution and Twin Cam style hydraulic tappets. They are not compatible with stock or aftermarket Shovelhead hydraulic tappets or most solid-style tappets..