Check the listing for details. Oasis GPX + High Tension Classical Guitar Strings GX1000H. Condition: New. Listed at 14.95 USD. Being a classical guitar player, I prefer powerful, punchy treble strings. I never could find a set of nylon trebles that met this criterion. A second problem I found with nylon trebles is the “tubby” sounding 3rd string. Instead of projecting a powerful clear sound, I just hear a dull or muffled sounding string. Fluorocarbon (carbon treble) monofilament solves both of these problems. We actually use two types of fluorocarbon. The 1st string is specially made from a fluorocarbon monofilament designed to eliminate string shredding, which is sometimes associated with fluorocarbon 1st strings. The 2nd and 3rd strings are made from a different fluorocarbon monofilament to enhance their particular tonal properties. Where the GPX+™ has really separated itself from the competition is the tone and sustain. One comment we hear about other fluorocarbon classical guitar strings is that they sound brittle or thin. Not so with our GPX+™ carbon treble strings. Most players feel that they have the beautiful tonal properties of nylon with the power and punch of fluorocarbon. GPX+™ carbon treble strings come in two tensions: normal and high. They also are available in a full high tension set paired with our high tension Sostenuto™ classical guitar bass strings. “These new carbon strings by Oasis are simply wonderful! With warm tone color and plenty of sustain, my guitar is now free to sing sweetly. Thankfully, my search for the optimum string is over. Bravo, Oasis!” - James Piorkowski, SUNY Professor and former member of the world renowned Buffalo Guitar Quartet.