Anderson connectors are used for connecting high amperage electrical wiring. They are genderless which means any two plugs of the same size and shape can be connected together.
They can not be connected incorrectly so are safe and foolproof for connecting power cables in the dark if needed.
They are widely used for connecting 12 Volt DC wires when camping in caravans or even boating and fishing and RVs and are very popular for connecting solar panel power supplies.
There are two single connectors per packet with contacts that require soldering or crimping to the cable ends. They are colour coded red and black for DC wire, usually positive and negative leads of a DC power supply.
They have a clever slot and key design that allows them to be stacked together to create customised multiple connectors.
UL rated to 45A DC, they are compact enough to fit in tight places but rugged enough to handle most current loads.

Two connectors per packet (1 red and 1 black) 

Specifications:

• Contact Rating: 30A
• Voltage: 600V (AC or DC)
• Contact Wire Size: 2.1mm2 - 5.3mm2 (#10-#14 AWG)
• Max Wire Insulation Diameter: 4.4mm
• Contact Retention Force: 9kgs (20lbs)
• Operating Temperature: -20 to +105ºC