Has anyone tried the Nurture Pure Wide Neck Nipple adapter?

I'm curious of 2 things:

A) Is its purpose to allow Wide bottle nipples on a standard size bottle, or Standard size nipples on a wide mouthed bottle (or both interchangeably)?


B) If the second half of the above question (standard nipples on wide bottles) is true - is the adapter compatible with Nuk wide-necked bottles?

I can't find large Nuk bottles (ie - 300ml or larger) that have a standard nipple cap anywhere. Or any large capacity standard bottles that I really like for that matter. I'd like to be able to have more than one bottle that I can use my Nuk5 nipple with.

The size 2 nipples I have are alright...but I prefer the 5.