This is what I use on the rivers at home and abroad. It rarely lets me down. The thickness to strength ratio is like nothing else I have ever used. I have landed brown trout over 5lb on the River Clyde using the Up to 3 Kilo (0.12mm)
0.10mm - Fish up to 2kilo (4.4lb) - Neil Sinclair (Double Decker) Dry fly master loves this for his Dries
0.12mm - Fish up to 3kilo (6.6lb) - I use this for dries down to size 22's
0.14mm - Fish up to 4kilo (8.8lb) - I love this for Drys down to size 16's
0.16mm - Fish up to 5kilo (11lb) - My Personal Favourite for Nymphing
0.18mm - Fish up to 6kilo (13.2lb) Stillwater Use
0.20mm - Fish up to 7kilo (15.4lb) Stillwater Use
With 150 m on the spool you cant go wrong at this price, imported directly from the manufacturers in Poland, No more expensive transit from Eastern Europe you can get it direct from Fly Fishing World.
I have not used this that much on the Still-waters, but I'm sure it will be fine in the 6 and 7 kilos sizes. I DO NOT RECOMMEND USING THIS ON STILL-WATERS DUE TO THE NATURE OF STRONGER RODS, HEAVIER LINES AND MORE SAVAGE TAKES FROM RAINBOWS AND BROWNS IN THE LOWER SIZES.