Wago 2773-2401 In-Line Push-Wire Connector  

The Wago 2773-2401 is a PUSH WIRE Inline Splicing Connector, designed for solid and stranded conductors.
This plug-in through connector is the perfect product for connecting wires in the smallest of spaces with a slim design perfect for tight areas. With many possible applications - extending wires that are too short or repairing damaged lines, can be achieved quickly and safely - without the need for tools.