Tonica Series Violin E String 4/4 Size Steel / Aluminum Medium Ball End. Tonica E string for violin. This is a new formula synthetic string available in a variety of styles. It is characterized by a lively, ope and direct tone. It additionally features great projection and brilliance, and an easy and fast response. It is not sensitive to humidity, is quickly tuned, and has a well-balanced set harmony. Attractive price, excellent quality.