Polymerized plastic with additives patented by Aquila.
This is a full set of 8U Nylgut Wound Low G Concert ukulele strings. It's Low G tuning in the key of C with a wound 4th. Strings are Nylgut (polymerized plastic with additives patented by Aquila) and multi-strand Nylgut overwound with silver-plated copper. Made in Italy.