The renaissance lute f-4 octave string is made from gut that undergoes a special process to make it as hard and durable as possible. Only the very best, most pure ribbons of beef gut are selected for use in the lute treble strings. It is available with a natural finish, or can be varnished at an additional charge. Standard-Gauges Lute Strings are available in three gauges, light, medium and heavy. If you require other gauges, please order from the "Custom Gauged Strings" section of the string store.