These are the same banana jacks we use on our 12 volt Power Supplies, they are actually "binding posts", in addition to a male 4mm banana plug they will also accept a bare wire or a U-shaped "fork" connector. There's a small hole drilled through the post just under the bottom of the plastic housing, unscrew the top section to reveal it, insert the bare wire into the hole or position the fork terminal around the post, and screw the top back down on it to hold it in place.  You can even use a small alligator clip, just insert one jaw down into the post and clip it around the plastic housing. The mounting hole required is 8mm, double nuts allow you to lock it in place so it won't turn or move.  The insulated housing isolates the wires connected to it, so these jacks can be mounted onto a metal housing or box without any problems, the jack will insulate your wires and keep them from shorting out to one another. These are much handier than a plain banana jack, and easier to mount.

Weight:  10 grams (per pair)