This 3x AA battery, switched battery holder come compete with a terminal connector on the end of the wires. These are perfect for connecting LEDs without the need for soldering.

These are not intended for use with a BBC micro:bit as the connector is not compatible. 

The batteries are fully enclosed in plastic case, which is secured in place by a small screw. The unit incorporates a small on / off switch. The leads are approximately 130mm in length and colour red and black to show the polarity of the connector.