Sleepers in Sterling Silver; in sizes between 11mm and 80mm. I wouldn't recommend sleeping in the larger sizes...
Most sleepers are made of hollow tubes and they are similarly shaped to a small hooped earring. They are often worn in bed so as to stop a pierced ear from closing up, hence the name.
Sterling Silver Jewelry pieces that are not worn for extended periods of time can corrode and tarnish as well. You must ensure your jewellery is clean and dry before storage; since any moisture, dirt, oils or other residual chemicals will accelerate the tarnishing. Clean silver after wearing with warm water and dry with a soft cloth, and store silver items in an airtight container with a piece of chalk or a silica pack; the little bags you find in shoe boxes etc.