This item includes 4 Enersol Header End Connectors (HEC) black ASA weather resistant polymer 13 1/2 long (4 Pack). Clips into system as a spacer, or can be used as a connector at the inlet and outlet of the system. The HEC can be used as a connector at the inlet and outlet of the bank of panels or as a spacer in the bank to bridge an object on the roof (i.e. skylight).