Synthetic core (Titanium wound E string) strings produce rich, complex tone. Settles in within 2-4 hours, unparalleled tuning stability, exceptional playability. Vision strings (available for 4/4 - 1/16 size) are designed for advanced violinists, Vision Titanium (4/4 size only) are for soloists. Vision Titanium Orchestra (4/4 size only) are lower tension, have a richer and warmer sound, and a feel and tone quite similar to gut core strings.