DC電源轉接頭（公頭），2.1mm桶形插頭轉螺絲端子

The labeled screw terminals made it incredibly easy to tell positive from negative without guessing. I used one to power an old router, and the screw-on connection feels much more secure than just twisting wires.

The labeled positive and negative terminals made wiring my LED project foolproof—no more guessing which wire goes where. I bought a second pack just to have spares on hand for future builds.

Finally, a simple way to connect bare wires to a 2.1mm barrel plug without soldering. The screw terminals are clearly labeled, so there's no guessing which is positive and negative. Having five in a pack is perfect for my various DIY power projects.