Either as a replacement for one of our bottles or to repurpose a glass bottle you have, this lid is for a 28mm neck.
The reality of DIY is that a glass bottle will last indefinitely but often the plastic lids take a beating from constant use. Natural mixes can often clog the spray pump over time. No need to buy a whole new bottle just replace the lid
All of our 500ml bottles are 28mm, and it is the most common neck size for these types of stray bottle.