Note: The scale needs to be placed on a sturdy, level surface. it doesn't work on carpets or rugs. Includes health tracking integration our iOS and Android app will sync data, monitor trends, provide health tips, and connect with fitness applications, such as Fitbit and Google Fit. One scale and unlimited users make the Rollifit scale excellent for sharing in group environments, e. g., large families, gyms, and nutritionists office. To maintain longer battery life, the scale data syncs via Bluetooth only when you tap the "Tap to Connect" icon in Rollifit app.