One group of these objects is sometimes named after Walter Kaminsky, and Kinney and Staley proposed a model for their synthesis. Solvay produced the second (*) generation of these objects, which are characterized by the presence of a Lewis base, while the third generation is supported by magnesium chloride. Cossee and Arlman described a namesake mechanism of their action. 
One group of these objects is sometimes named after Walter Kaminsky, and Kinney and Staley proposed a model for their synthesis. Solvay produced the second (*) generation of these objects, which are characterized by the presence of a Lewis base, while the third generation is supported by magnesium chloride. Cossee and Arlman described a namesake mechanism of their action.   With the exception of a few containing vanadium, these objects are almost always heterogeneous.  Industrially, these objects are most widely used in the production of polypropylene and polyethylene, though they can be generally used to polymerize any alkene.  For 10 points, name these catalysts often containing titanium and aluminum, named after a German and an Italian chemist.
One group of these objects is sometimes named after Walter Kaminsky, and Kinney and Staley proposed a model for their synthesis.
{Ziegler-Natta} catalysts [prompt on {catalyst}s before “generation”]