Thomastik KF110 Classic S Set

Great, low tension strings for classical guitar when you need a rather "metallic" - acoustic guitar sound with no danger for the instrument. Excellent quality.

These are great strings, but be aware that they are great only for particular purposes.
The strings feel like nylon but are metal covered. This makes them great for playing fingerstyles like latin jazz or fast jazzy stuff in general (due to their fast slick feel).
I use them for this and I love them for their sound, speed and noiselessness. However if you just want to strum out a few chords you would be better with real metal strings for a more punchy sound.

Background: I installed these strings on a DIY fretless classic guitar. The fact that it was fretless made the usual nylon string lack of clarity and treble compared to a "normal" classic. These strings provides the extra treble needed, and give my guitar a very unique sound, whilst increasing the overall sustain.