We offer AFS GFN identifiers for each of our foundry products. We prefer that you send us a sand sample to be tested so we can accurately recommend an appropriate size for your facility. In general, our AFS 100 is used by shops that pour only aluminum and have automatic molding machines. AFS 115 is typically used by shops that have squeezers, etc. and perhaps pour some brass. AFS 130 is used for belt buckles and plaques. AFS 145 is the next step finer.