This plain washer is a necessary component for the proper function of Cummins Engine models KTA19, KTA38, KTA50, and NT855. It is manufactured in China and comes as a single unit. The manufacturer part number is 139990-20. This washer is designed to fit perfectly in your engine, ensuring smooth operation and optimal performance. It is an essential part that is required to maintain the longevity and reliability of your engine. This plain washer is a genuine replacement part that meets the high standards set by Cummins. Purchase with confidence knowing that you are getting a quality product that will keep your engine running smoothly for years to come.