PLA (Polylactic Acid) is a biodegradable thermal plastic derived from corn starch, tapioca root or sugarcane. Prints with PLA have a shiny type look and are less likely to warp and bend during the print process. PLA is great to use when sharp clean edges are desired. Prints made using PLA are often very hard, (we have made a few ice scrapers with ours) and are also safe to use when creating toys. Our spools are made to a strict 1.75mm diameter.