Soldering directly onto Flexible LED Strip can be difficult for some and often result in burning the LED Strip, or your fingers.
These are small plugs that can be used for joining LED Strips without having to solder onto the actual LED Strip
This version is for the 4 Wire LED Strips that is usually: VCC, GND, CLK, DATA. This setup is commonly found with WS2811 Strips and other common RGB LED Strips.