From Absolute Attention:
No matter if you're timing an egg or a marathon, Digital Timer is a gorgeous, reliable, accurate and absolutely free app for your Android phone. Features include:
No ads, no spam, no popups.
Beautiful and simple design that utilizes the entire screen for touch
Stopwatch and Countdown optimized modes, including alarms.
Zero-drift timekeeping engine will keep your results accurate under all conditions.
Zero power usage when the app is in the background or the screen is off.
Use the volume Up and Down keys to Start, Pause and Reset the timer.