Aquila's 106U Super Nylgut are a set of pearl-coloured strings for tenor ukulele. These strings are made of a very strong material, namely super nylgut.
Aquila's 86U Red series concert ukulele strings are made of Super Nylgut with copper powder that gives them their red colour. They produce a bright, powerful sound and are suitable for GCEA tuning with a low G.