You can wear the Fitbit One comfortably in or on your pocket or on a bra. The silicone clip will keep it secure.
The One is not designed to be worn in direct contact with the skin. Always use the silicone holder when clipping it to a bra or waistband, with the display facing outward. Do not wear the One inside your bra.
Some users may experience skin irritation even when wearing the One as instructed on the bra or waistband. If this occurs we recommend clipping it on your pocket, belt, or other external piece of clothing.
Use the sleep wristband to track your sleep when you go to bed. Note that the wristband is intended for sleep use only; if you wear it during the day to track your steps, your One will be less accurate than usual.
You should keep your Fitbit One dry whenever possible. The Fitbit One is not waterproof, but it is rain, splash, and sweat proof. It should not be worn while swimming.