New Warchal Amber strings feature W-Core, a new synthetic core material developed by Warchal to produce the rich warm sound of gut strings with the tuning stability of modern materials. The Amber E string in the set is based on a unique spiral helix design. Standard D included in sets is hydronalium-silver wound.
I have been using the Warchal Amber strings for a week and have found them very rich in tone and easy to play, very similar to Peter Infeld PI. They took a few days to fully settle. The Warchal Amber E has been my standard E for a few years. Other players have been giving high compliments to the sound from my F. Ruggeri.