Warchal Brilliant Cello String Set - Synthetic Core - Medium Gauge Full Cello String Set For 4/4 Cello Medium Gauge A String: Synthetic Core - Hydronalium Winding - Ball End | D String: Synthetic Core - Hyronalium-Silver Winding - Ball End G String: Synthetic Core - Tungsten-Silver Winding - Ball End | C String: Synthetic Core - Tungsten-Silver Winding - Ball End