The Helicore Octave Violin Set is designed to be played one octave below traditional violin tuning for a new world of tonal and stylistic possibilities. It utilizes the same core technologies as the original Helicore violin set. This set is considerably thicker than traditional violin strings. As a result, they require extra care to ensure they are properly installed on your violin. Please follow these guidelines for installation: Check that the grooves in your bridge and nut have room to accommodate the diameter of the octave strings. Excessive pressure or pinching may prevent normal movement. For best results, thoroughly apply graphite (pencil lead) to grooves before installing each string.