Masterpiece Artist Canvas 45815 3D PRO 2-1/2" Deep, 12" x 12", Cotton 14.0oz - 3X - Sausalito Heavy Weight Heavy weight 100% cotton, 11.5 oz raw weight, 14 oz finished weight. Canvas is strong and tough and has a robust paint-gripping surface texture. Sized and double primed with archival quality acrylic gesso. Canvas Depth: 2-1/2", Canvas relief: 1/2" (Space between canvas and Bar). Solid Pine or Fir Stretcher Bars from the sustainable forests of the Pacific Northwest. No finger joints are allowed, which tend to fail under pressure and over time. Precision machined double tongue-and-groove corners allow you to increase the canvas tension. No Brace Required for this size. Corner keys are pre-installed. Stretched using our MuseumWrap method yielding a balanced tension across the surface of the canvas, and a drum-tight stretch that is up to 50% tighter than other methods. Folded corners mean a canvas that is uncut and perfectly intact, allowing the canvas to be removed from the frame and re-stretched.