This is a set of six high pressure rail plugs. They are made to be used on heavy duty high pressure oil and fuel systems. They are compatible with 2007 MaxxForce 11, 2007 MaxxForce 13, International S13, Lonestar, Paystar, Prostar, Transtar, Workstar, and 12 engine systems. This is a replacement to the ZTSE4900
