What is a loop end violin string?
Most modern synthetic core or metal strings have a loop on the end with a metal ball in it, but some, especially some of violin E strings and an occasional viola A, are available with a loop and no ball. ... The result is that there is less string length between bridge and tailpiece.
What is ball end string?
Update: Feb 27, 2016 - Removable Ball-End Strings are now a very popular type of Violin E string and Viola A string. These strings have a ball end that can be removed to reveal a loop-end. Not all ball end strings are removable! "