Universal

I don't know if I understand the question, but the attachment we bought for our Hitachi is a "universal" attachment that we bought from another store. It's too "floppy" for me, but is a nice g-spot attachment, or would be if it was a little stiffer!

There are a number of third parties that make slip-on covers for the hitachi. Trinity, IMHO, has the most interesting ones. These are all highly subject to personal preference, so shop carefully.