Four-pole terminal block. Use these heavy-duty terminal blocks for interconnecting wires of all sizes. Electrical connection exists between opposite screw terminals and one or more wires may be attached to each screw terminal. The three different sizes have respective lengths of 1-1/2", 2-1/4" and 3". CK1049 is a Two-Pole Terminal Block. CK1049-1 is a Four-Pole Terminal Block. CK1049-2 is a Six-Pole Terminal Block.
These are a good item for use if you plan on expanding your electrical usage. I use them when wiring houses for customers. We wire each floor of the house separately but initially bring all the floors together and tie them in using a Terminal Block. Then, as the customer adds more lights to their house, they can split off one or more floors using separate transformers for one or more floors.