Simple, it works. I don't wear glasses, so I don't have issues with fitting them in with the breath box. It's a great product, because I no longer need to Crack or open my visor to prevent fogging at the light. It does require a minimal amount of prepping before install, and an alcohol wipe is provided. This is a one time use product. Overall I'm happy with it, and will purchase it again before next winter. I'll wear the current one until summer time. Thanks STG!!!