D'Addario EJ51 Pro Arte Recording Classical Guitar Strings Hard Tensionstar rating 5PhilipJune 3, 2010These strings eliminate the annoying squeek one gets playing wound nylon strings. Polished basses I've used from other manufacturers lasted about 3 weeks. These strings last 3-4 months. IOW when they are dead they break. Worth the $$$ and then some. I won't use anything else.