It looks like circle cutters to me. I've used Wilton's silver color mist spray to get that look before! It takes a couple of coats.
ok, I actually think I might have that wilton spray, Are there cutters out there that small that go up that little in size to make a ring like that? I might need to google search.
I know there's bigger sets out there that probably do have the right sizes. I tend to use my three circle set and then use piping tips to get the smaller sizes (the opposite end of your 1M, the size 12, etc).