Urgency Bear Countdown Timer

I downloaded this app, hoping to add a countdown on our out-of-stock products to inform our customers when the restocks would be. Unfortunately, the countdown doesn't work on out-of-stock products.

The support got back to me super-fast to help when it wasn't showing up. I'm only choosing four stars because the functionality could be better and the fact that it doesn't work on out-of-stock products could have been communicated in the documentation somewhere (or somewhere more obvious, since I spent an hour trying to make it work and couldn't figure it out.)