This app is an easy calculator for biological/chemical buffer preparation. By using this app, you can figure out the calculated weight of your materials in target volume water. If you type a material name, Auto complete text will show up to guide your selection. Also, you can add and delete your custom material to the Auto completion list and make the calculation fast and more desirable. It's an easy app as much as its function. Please contact me if you need some specific functions! I'll do my best to make it better!! Hope you get some convenience by using this app.