|Pirastro Wondertone Solo strings offer excellent versatility and outstanding playing characteristics. Wondertone Solo features a new synthetic core modified from Pirastro's leading performers, Evah Pirazzi, Obligato, and Violino strings. The result is nearly no break-in time and exceptional tuning stability. In addition, Pirastro introduces a steel core A string and Silvery Steel E string that are specifically designed to optimize set harmony. Pirastro recommends its Oliv/Evah rosin with these strings.