NEON helmets are designed to accommodate both round and oval head shapes. When using the online size finder, you’ll be asked to select your head shape.
Round head: width and length are similar.
Oval head: noticeably longer from front to back than side to side.
Selecting the correct head shape ensures a secure and comfortable fit.
If you need more help: https://unit1gear.com/blogs/stories/how-to-find-your-helmet-size-for-bicycle-helmets