I use both plugs from BJC, the locking plugs have two locking set screws to keep wire in place and a screw on barrel to force the pins of the plug to expand locking the plug very securely in place, makes for an excellent connection, well worth the extra $. I move equipment around a lot and don't have to worry about the plugs coming loose, I believe they are $5.50 a pair, they don't resemble the unique plug.
Jeff