The bridge maple wood has undergone A.R.E. treatment (*1) to enhance sound quality and response. The shield cover (*2), which is mounted on both sides of the bridge in the YEV104/YEV105, is reduced to one side for the YEV104PRO/YEV105PRO, allowing greater bridge movement for capturing delicate bowing nuances. (*1) A.R.E. stands for Acoustic Resonance Enhancement, a technology that replicates the sound of aged wood. (*2) The shield cover minimizes noise when connected to amplifiers.