Review on RONYOUNG Sandglass Colorful Hourglass Classroom by Rachel Coppedge

They are great for what I need them for. They are not exact but it was said on the page. The main issue I have is that some of them require you to press down on them a bit to make them run. The sand seems to clog and not flow. I use them to tell time and I need them to flip them because once you flip them you have other tasks to complete. The problem is that if you don't hit them a little, they won't start, you might not notice, and when you finish your tasks the sand is still sitting on top.