P41A011 Pirastro Perpetual Cadenza violin string set P31A111 Pirastro Perpetual Cadenza violin string E-1 P41A211 Pirastro Perpetual Cadenza violin string A-2 P41A311 Pirastro Perpetual Cadenza violin string D-3 synthetic core P41A411 Pirastro Perpetual Cadenza violin string G-4 synthetic core