I don't know what the proper name is for these I have always refered these as "Squirrel Clamps" or "Squirrel Cages" I have one for 4" and one for 6" Both have barely been used. Most you find used have been hammered on these how ever have only used once. I will sell both for 100.00 or 75.00 a if you only want one. Shipping will be extra and will ship how ever your preference. Call Stan @ 580-761-1877 for any other details. Thanks