Review on Swpeet Hourglass Sandglass Assortment Including by Melissa Brown

I'm not looking for synchronization with an atomic clock or anything else (this technology is available to anyone with a smartphone). Maybe half a second or even 1-2 seconds would get me thinking about holding them, but 3 minutes was 12 seconds early and 10 minutes was TWENTY-SECONDS TOO LONG! This is unacceptable. return these. Pros: Glass looks/feels good. The size is enough to fit in one hand. Cons: I didn't pay attention to the huge bead of glue holding the inside of the plastic lid. Without a terrible inaccuracy I would have given 5 stars. Can moisture changes that react with paint on sand cause unexpected friction? IDK just a thought. Requires quality control/calibration prior to shipment unless intended for decorative use.