Somebody buys a sleep mask because the room is too bright, or because a person they like sleeps badly. It is a small gift with one job: make the morning start later.
This page is the rest of the house. Sleep masks sit here, the kind that stay on a nightstand. So do the other things that stay where you put them: a blanket for the couch, a mug, a poster, a bottle that lives on the counter. The mask is the quiet one. It has one job, and you know by the second night if it does that job. The mug and the poster can be the loud ones.
Look at where it will sit before you send it. A mask wants a strap that is still comfortable at one in the morning. A mug should read from across the room. A poster needs a wall with empty space. If you are buying for someone's home, pick the thing they will bump into every day.