What is a box canvas?
 
A box canvas, also known as a profile or gallery canvas, is a type of art canvas with a thicker stretcher bar that provides more depth than a standard stretched canvas. 
 
This added depth allows artists to paint the sides of the canvas, creating a finished look that can be hung without a frame. 
Box canvases offer a bolder, gallery-like presentation, are generally more stable, and are built to withstand heavy-duty art techniques.