What size is extra wide in New Balance?

Excuse me, could you please clarify the sizing for New Balance's extra wide option? I'm interested in purchasing a pair but I'm unsure of the specific measurements or how it compares to standard widths. Is there a specific width designation for extra wide, or is it a general term that varies by shoe model? Additionally, do you have any recommendations for customers who require extra width to ensure a comfortable fit? Thank you for your assistance.