Anyone who works in a lab knows that dealing with staining of microscope slides is messy and annoying. This device holds the jars in strict alignment and is heavy enough to make tipping over nearly impossible. Having the jar lids all connected makes it much more convenient to open the jars and start staining, and, more importantly to close the jars when you are done. These holders were made in translucent acrylic and feel really solid and unbreakable.