These beautiful and classic designs come in a variety of colors and sizes. Available in 5, 15 and 30-minute timers, in natural stands. Our largest Sand Timers come in 50, 90 and 100-minute timers in natural stands with yellow sand. An hourglass, also known as a sand-glass, sand timer or sand clock, is a device for the measurement of time. The hourglass is named for the most frequently used sand-glass, where the sands have a running time of one hour. Once all the sand has run to the bottom bulb, the device can be inverted to measure time again.