As the name suggests, this manual Charge 5 feature helps you lock your Fitbit Charge 5 when getting into showers or before going to swim. This feature was not included with the Charge 4 and helps you maintain your fitness device and prevent unnecessary water damage to it. Basically, it locks all buttons to prevent activation by water. However, note that while your Fitbit device is water resistant, it is not completely waterproof, and contact with corrosive liquids like soaps and shampoos may damage it.