Stanadyne/Clarcor Fuel Screen, part # 29244. Genuine OEM replacement part from Clarcor, the parent company of Stanadyne. Item is brand new in factory sealed package as seen in first three pictures (additional pictures for reference only).
This “strainer”, as it is often called, installs inside of the fuel filter housing (Fuel Filter Manager) on all 6.5L GM diesels. It is extremely common for the strainer to stick to the bottom of the fuel filter and get thrown away when a new filter is installed. It is an important component designed to keep large particles/debris away from the injection pump in the event of a fuel filter failure. This will fit all 6.5L diesels regardless of application or model year.