3 Sets 5.5mm x 2.1mm Male DC Power Plug Connector & Screw Lock Female Panel Socket Mount Adapter

I chose these plugs and jacks because of the price and the novelty of the locking feature. You can use them with or without locking them together. Of course locking the plug and jack makes for a better connection (at least for the ground portion due to the screw-on collar). The machine tolerances are what you might expect from a $3 jack/plug pair (i.e., not suitable for Aerospace applications, but fine for hobbyist use).NOTE: the switch portion of this jack acts in an atypical manner. It uses a normally closed switch between the ground terminal and a third terminal. Inserting a plug into the jack disconnects the ground terminal and the third terminal. In 35 years of messing around with electronics, I’ve never encountered a power jack with a switch design like this.A typical power jack uses a normally closed switch between the center pin (+ terminal) of the jack, and a third terminal. Inserting a plug into the jack disconnects the center pin of the jack from the third terminal.

Listing and price show THREE sets of connectors and sockets but seller only ships TWO sets.Otherwise, connectors are as expected. Locking ring not needed or used for my application.