– The Nano Ufo came to our mind in Norway August 2012, low water, clear like gin, that was the condition we where fishing Lakselv at.. The tubeflies was so small, and then we realized we needed this NanoDisc.. It works very very good on the small tubeflies, but also on bigger flies it works.. To finish a fly with this little disc is just to easy.. FF Nano Ufo Disc is 4.5mm with a hole size of 1.9mm Comes in 7 colors.