This JHR Billet Screw On Breather kit is just what the doctor ordered. Proper crankcase ventilation is vital to an engines performance and durability. When you have a high performance engine the crank case presures can rise to the point of creating leaks and contaminating the engines combustion leading to major engine failure. Don't let an easy fix cost you the race or even worse, cost you a motor! This kit comes complete with a billet aluminum female bung that welds to the valve cover, a billet CNC machined filter adapter the screws into the female bung and a 1-3/8" slip on breather filter. As an added benefit this kit also serves as an oil fill location. Buy the best. Buy Genuine JHR products!