https://play.google.com/store/apps/details?id=com.greendigitalmedia.refplayclock
This Google Wear OS app allows high school and college referees to take the play clock (25/40 seconds) for football games without the use of an expensive stand-alone device. Simple delay-of-game timer for football referees with an Android Wear OS smartwatch. You can track 60-second timeouts as well.
For ease of use, there are two color modes, white background for daylight viewing, and black background for night viewing. To switch between them, simply press the icon at the top of the screen. The color mode will toggle back and forth each time you press the icon.
For timeouts, select the green :60 button at the top, and the timer will be set to :60. Press the Start button and the countdown will begin, the timing mode buttons become disabled, and the Start button changes to a Stop button. If the Stop button is pressed, the countdown stops, the timer is reset to :60, and the timing buttons are enabled.
With 15 seconds remaining, the timer text color changes to yellow and the watch will vibrate for 1/2 second, and with 5 seconds remaining, the text color will change to red. When time has expired (:00), the watch will vibrate fro 1 second, the display will stay at :00, and the Stop button changes to a Reset button. Press the Reset button to reset the :60 timer and enable the play clock timing buttons (:25/:40).
For the play clock, select either of the yellow :25 or :40 buttons at the top, and the timer will be set accordingly. Press the Start button and the countdown will begin, the :60 timing mode button becomes disabled, and the Start button changes to a Stop button. If the Stop button is pressed, the countdown stops, the timer is reset to either :25 or :40 (whichever mode you selected), and the timing buttons are enabled.
With 10 seconds remaining, the timer text color changes to yellow and the watch will vibrate for 1/2 second, and with 5 seconds remaining, the text color will change to red. When time has expired (:00), the watch will vibrate for 1 second, the display will stay at :00, and the Stop button changes to a Reset button. Press the Reset button, or either one of the play clock buttons (:25/:40), to rest the timer and enable the :60 timing mode.
A convenient feature of the play clock is that it can be reset while it is running. If the :25 or :40 countdown clock has started, it can be easily reset and re-started, automatically, by simply pressing either of the play clock buttons at the top. For instance, if you are running the :40 clock, and it runs down to :15 and the referee needs to reset to :25, you simply press the :25 button, and the timer will reset to :25 and start counting down. No need to stop, change timing modes and start.
Once the timer has been reset, you can select a different timing mode by pressing one of the buttons at the top of the screen (:25/:40/:60).
Is compatible with the following devices:
Asus ZenWatch 2
Asus ZenWatch 3
Casio WSD-F20
Casio Smart Outdoor Watch WSD-F10
Casio PRO TREK SMART
Fossil Q Wander / Q Marshal / Q Founder 2.0 / Bradshaw / Dylan
Fossil Fossil Sport
Fossil Wear
Fossil Q Founder
Fossil Gen 5
Guess Wear
Huawei Watch 2
Huawei WATCH
LGE LG Watch Style
LGE LG Watch Urbane
LGE G Watch R
LGE LG Watch Urbane 2nd Edition LTE
LGE LG Watch Sport
Louis Vuitton Tambour Horizon
Mobvoi TicWatch Pro
Mobvoi TicWatch C2
Mobvoi Ticwatch S Smartwatch; Ticwatch E Smartwatch
Mobvoi TicWatch E2/S2
Mobvoi TicWatch Pro 4G
Montblanc SUMMIT
Motorola Moto 360 (2nd Gen)
Movado Boss Touch / TH 24/7 YOU
Movado Connect
New Balance Run IQ
Nixon The Mission
Polar M600
Samsung Gear Live
Sony SmartWatch 3
TAG Heuer Connected
TAG Heuer Connected Modular 41
TAG Heuer Connected Modular 45
Verizon Wireless Wear24
ZTE Quartz