These ten power Jacks all tested good out of the box with an ohmmeter. After you strip 1/4 inch of insulation off of the wire, you might want to tin the wires with solder, in order to ensure a stray strand of wire doesn't accidently short against the adjacent confuctor. A thin flat-blade (common) screwdriver secures the wire to the jack. There are small "plus and minus" signs to indicate where each wire goes. The plus sign terminal is connected to the center conductor. You have the ability to reverse polarity on this jack, so you might want to test your powered-up jack with a volt meter before applying it to your equipment.

I ordered a new security cam for an older security camera system. The old power cable was a basic "bare wire" connection to 2 screw connections. The new camera power connection was a very nice DC power adapter female jack. This power adapter provided easy connect adapters to connect the old bare wires to the adapter, and a quick connection to the power connector on the camera.
Not sure what I would have done if I hadn't located these adapters. Changed a real problem into a 30 second solutions.

These terminal ends are exactly what I was in need of in order to make connections with small gauge wires going to D/C powered devices. I use them mainly for CCTV cameras and IR illuminators as well as various other gadgets that require an A/C adaptor. I am using a multi port power supply in order to do away with the multitude of adaptors that require a 120VAC outlet in order to get power.
These connectors are easy to use and they make a tight connection that doesn't easily pull out.
These connectors do not require wire nuts, solder, or any other additional electrical hardware.

The price is great, and while these are often used for security camera power connections, they are also standard for a lot of Remote Control (R/C) First Person View (FPV) equipment.
i.e. often used for the ground station equipment running on 12V DC: remote video receivers, diversity equipment...
I find it particularly well adapted for that R/C usage as the length of the cables can vary quite a lot depending on the antennas position, and it's super fast to attach a cable to that connector.

I found the "+" marking to be connected to the center contact on the batch I received. As I wanted to make these center positive, that worked great.
In all cases, please check with a multi-meter to see what post connects to center, and what polarity your equipment requires. [measure twice, cut once would be more like measure twice, avoid smoking your electronic equipment).

This is a great adapter if you need to make quick and easy connections for 2.1mm ID / 5.5mm OD plugs. The screw-down clamps make quite a secure connection, but be careful not to overdrive the screws. One of the 10 pieces had a faulty screw clamp - it wouldn't seat correctly even after I stripped it down, but not a big deal. I use these to test out RC FPV circuits and once I'm happy with the layout, I replace these with soldered connections. For applications that are not critical, you could probably get away with using these adapters permanently.