To get the perfect fit with your VivaRays mask, follow these steps: 1) Place the eye cups spaced far apart along the head strap and try the mask on. 2) If you do not get 100% blackout, detach the eye cups and place them slightly closer to each other and try the mask on again. 3) Repeat this process until the eye cups are just right and you get 100% blackout. You can also watch this video: https://www.loom.com/share/4f041615aa6e4f3d8e1e3ae783dbd0c5