Warchal Amber Viola StringsWarchal Amber Viola Strings : The metal core A string benefits from our helix design which gives the metal core exceptional elasticity and results in a new level of sound quality. The Amber string set is complemented by an exceptionally beautiful and luxurious silk winding design which is a jewel for your instrument. This is a great set of strings for an intermediate to advanced player looking to produce a beautiful sound from their instrument.