It doesn't mean anything in some cases, just a bit of marketing hype. In others it refers to a significant invention. Sometimes by the 'maker in question, sometimes referring to a use of someone other's patent, sometime royalty paid, sometimes not. Sometimes it will have been a provisional patent, never fully patented. Sometimes a tiny 'make-weight' part of a much more well known patent.
All in all, if it doesn't mention a specific date/patent no./trade mark/Use no., I wouldn't spend too much time on researching it.
You would do better to look at the mechanism and refer to David Baker's excellent books. He does get it wrong/make an omission occasionally but very rarely.
Have fun!
