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Extensions 
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Lightweight Alarm Clock, Timer & Countdown
Alarm clock, timer, and countdown with sound and desktop notification.
Tab Countdown Timer
A Chromium Extension that allows you to set a timer that counts down and then closes the tab.
Steep and Cheap Countdown Timer
Steep and Cheap sells outdoor gear one screamin'(50-80% off) deal at a time until time runs out. (steepandcheap.com)
Chainlove Countdown Timer
Chainlove sells bike gear for dirt and pavement one screamin'(50-80% off) deal at a time until time runs out. (chainlove.com)
Pokemon Countdown Timer
This is a fan-made extension that allows anyone to quickly check how soon the new Pokemon games will be released!
Whis'key' Militia Countdown Timer
Whis'key' Militia sells skateboarding gear one screamin'(50-80% off) deal at a time until time runs out. (whis'key'militia.com)