BEST Cross Braces are made from pine and designed to brace the backside of your stretched canvas. Each brace is center notched allowing for simple T-bracing of most any dimension canvas. More elaborate bracing configurations can be created by simply adding notches in the appropriate places with a saw. More complex bracing systems can also be custom ordered. Our brace profile is 13/16-inch by 1-3/4-inch. The brace lengths have all be calculated to fit the length bar you are trying to brace. For a BEST Heavy Duty 36-inch bar (for example), be sure to order a BEST 36-inch Heavy Duty Brace. The actual brace length is only about 32-inch as it fits the interior of your frame. You must also purchase Jack Richeson's Cross Brace Bracket 2 pack separately with each brace. These brackets attach the brace to your frame, and have adjustment slots to allow for future tensioning of your canvas.