This has to be the best sleep mask I have tried! It blocks out all the light, and I mean ALL the light so these mornings when the sun is up at 3 am are no longer the start of my day. What is different here is that the mask fastens securely round your head, and doesn't slip like those masks with the elastic bands. Thank you to Sarah who sent my mask so promptly, so I could use it straight away. Would definitely buy again!