The Cat Pumps 30243 is a pack of parts used for direct mount pumps. It includes 4 studs, 4 nuts, 4 washers, and 4 locking washers. Compatible with 4FR, 5FR, and 5PFR+ pumps. See list below for compatible models. Parts in the kit are made with steel plated zinc. These are OEM parts from CAT Pumps.