Samsung Galaxy Ring

The easy choice for Samsung phone owners, and a closed door for iPhone users: it works only with Android, and some extras such as Energy Score work best on a Galaxy phone. In return there is no monthly fee, so the $399.99 US list price is the whole two-year cost. The grade-5 titanium band is 7 mm wide and 2.6 mm thick and weighs under 3 grams in most sizes, which makes it easy to forget overnight. Samsung rates sizes 12 to 15 at up to seven days per charge and smaller sizes at up to six. There is no vibration motor, so no silent alarm. Eleven sizes run from 5 to 15, so use Samsung's sizing kit before you order.