A little while a go I wrote about my E-koi helmet. It turned that a few things weren't clear yet. So here are three photos to explain things better. The first post I wrote about this helmet is here. The little bolt I used comes from an old Quest velomobile mid-drive. The 3mm bolt replaces the silly little screw.
The foam around the helmet straps on the third photo is there to reduce wind noise. It's nothing more than a piece of foam held together with a staple.