We use these QALO rings when we are traveling as they attract less attention because they aren't metallic and shiny. At a price of only $15-$35 they are much more affordable to lose if they were stolen or fell off. Additionally, they are made of silicone and can be used in the water or while doing something a bit more adventurous than normal (rock climbing, canyoning, etc). They are meant to break if they get snagged on something dangerous, unlike a traditional ring, and therefore prevent injury or loss of your finger while exploring.
They are very comfortable and come in various widths. If you are between sizes, you might want to size down for the thinner rings and size up for the wider ones. We each got two in different colors because we liked them so much.
If you're interested, you can get $5 off by using the link below.
Take a look at QALO Rings.