Those look about like the ones I use to connect from my amp cables to my subs in my car. Dunno if there are different widths, but I would think that there would / should be. Also, I believe these are sometimes used to connect to electronics-lab equipment like the nicer bench-top multimeters etc.
In a pinch, when these were all that I had handy and they wouldn't fit where I needed. I have cut the plastic apart with some large wire-cutters and made singles out of them.