Mustache Watch Face is a free personalization app designed for Android wearables. It offers a variety of features, including 14 themes, optional date and 12-hour clock indicators, leading zero, and sweep second hand. It also provides analog and digital clocks, tick marks, and big digits in ambient mode. Users can customize the watch face with an optional badge, choose from 12 premium themes, and select second hand and ambient mode colors.

The app also offers additional features such as phone and watch battery level indicators, ambient mode with low-bit and burn-in protection, mute mode, and night mode with automatic style change. Users can interact with the display to access weather and fitness data and tap to launch apps such as the calendar, fit, and weather apps. The app requires Android Wear 5.0 and permissions for coarse location to compute sunrise and sunset times.

Mustache Watch Face is created by Eric Plaquevent and designed by Manu Mercadal. The Android Wear Flat Device Frame by Cyril Mottier is also used in the app and licensed under CC BY 3.0. Overall, Mustache Watch Face is a fun, customizable app that offers a variety of features for Android wearables.