This 15x48 is one of our Extreme Rectangle sizes in the 16:5 Extended Panorama. Raw Unprimed #12 cotton duck heavy duty canvas weighs 11.5 oz.. Take control of your art by preparing and priming your own surface texture, or use bare expanses of canvas as part of the art work. It works great for staining or pouring techniques in which the fabric threads soak up the thinned paint, resulting in abstract color combinations, and a fluid and spontaneous convergence of the image and the fabric, not possible with pre-primed canvas. There is a 1/2" gap between the canvas and frame, eliminating the unwanted lines that occur when the gap is less. We never use finger joints in our wood frames, which often fail under tension and over time - the glue joints give-up, and are unsuitable for paintings intended to last for centuries. Patented 3.25" wide heavy duty keyable brace allows the canvas frame to be tensioned in the middle, where the tension is needed the most! The Stretcher Bars are slotted in the center to accept the brace. Due to our unique design, the brace may be removed, if desired. Both corner keys and brace keys are pre-installed. Stretched using our proprietary MuseumWrap method, producing a drum-tight-stretch up to 50% tighter than other methods, and with balanced tension across the surface. The corners are uncut and neatly folded, making it possible to remove and re-stretch the canvas on the same size frame.