Neck fragment, is this design called a "double ring"?

[embe]

Found this today, lots of other broken glass in the area but this is the only one that *might* be identifiable, since it's a neck. I figured mid-century bleach or something like that, but the closest thing I could find online at sha.org referred a similar design as a "double ring"? Any input is appreciated. Sorry for blurry pic, been a long day and just started cleaning the dirt off.

 

[CanadianBottles]

I'm not sure if these have a specific name, I think of them as poison tops because they're almost always found on bottles which had poisonous contents. I've never seen confirmation of this but I've always assumed that specific lip design was meant to be a warning to someone opening the bottle without being able to see it. The illustration there is of a totally different type of top which was in use much earlier, around the mid-19th century.

 

[nhpharm]

Usually that style of lip is found on English bottles so far as I have seen (and often poisons/household chemicals as noted)...definitely not a double ring.