I got the whole setup in one nice kit. The punch cutter that can turn a mini-SIM* into a nano-SIM, or a micro-SIM into a nano-sim. A nano to micro adapter, a nano to mini adapter and a micro to mini adapter. Also a nano-SIM ejector that looks just like an unspooled paper-clip (except it's too short so I have to use the paper-clip after all) and a tiny piece of sandpaper, to shave a little off a mini- or micro-SIM, since the nano-SIM is just a hair thinner.

It all works, too. I took the micro-SIM I was using in my N9 and cut it down to nano-size (with great anxiety) and it worked in my OnePlus One and OnePlus X. Putting the cut-down chip in a nano- to micro-adapter got it working back in the N9. Putting it in the mini-adapter, and it works in the N900! I did not sand the label down, and it's just a little tight, but not so tight it gets stuck.

Now I wouldn't want to be switching these around all the time, but it's fine for occasional use.

*I know most people call the "mini-SIM" just a "SIM," but the original SIM really was the size of a credit card with the chip contacts in the same place you'd see on your Visa card (or whatever).