The Nano Ufo came to our mind in Norway August 2012, low water, clear like gin, that was the condition we where fishing in Lakselv. The tubeflies was so small, and then we realized we needed this NanoDisc. It work very very good on the small tubeflies, but also on bigger flies it works. To finnish of a fly with this little disc is just to easy.. FF Nano Ufo Disc is 4,5mm with a holesize in 1,9mm 10 in a pack