The 2mm wide line profile loop design makes it fast, efficient and filament consious to 3D print (5 min ea in my testing).  The internal loop hooks are printed line on line and with a flex of the part after printing, the hooks seperate.  This creates a secure pocket for the elastic straps to lock into the device, making the face mask and this strap holder a singular item of PPE when used together.  The open mid section design allows for comfortable and secure use at the top rear of the head while also at the bottom of the neck.  The light weight design is intended to be less noticable to the user while providing good comfort, flexibility and strength.