We sell these in packs online or they are available individually in store. Winsor & Newton’s new and innovative Professional Cotton Canvas range caters to the needs of those with the very highest quality demands. These canvases feature the unique new pro-stretcher device allowing for ultimate control over the surface tension. These canvases are hand stretched and have a 16.9oz/480gsm weight. The 42mm depth profile stretcher bars are produced from warp resistant kiln-dried, FSC approved, heavy-duty pine. Each Canvas is prepared, and ready to paint, with highly pigmented titanium dioxide primer for superior coverage and performance. Each canvas is also archival and acid free. For use with all forms of acrylic, oil and other mixed media applications. Available in a wide range of sizes in both metric and imperial. What's the difference between the Professional and the Classic Winsor & Newton Canvas range? Professional Classic Pro-stretcher™ tool Wooden keys for stretching Pine wood frames Spruce Fir and Paulownia wood frames Available in Cotton, Cotton Deep Edge and Cotton Fine Detail Available in Cotton, Cotton Deep Edge and Linen Heavier canvas cloth weight Lighter canvas weight    Winsor & Newton Professional Canvas Options Range Cloth Wood Depth Weight Cotton  Cotton Pine 21mm 480gsm Cotton Fine Detail Cotton Pine 21mm 280gsm Cotton Deep Edge Cotton Pine 42mm 480gsm    How to use the pro stretcher tool Insert the tool into each corner of the canvas With a screwdriver, tighten the device by following the direction of the arrows. Tighten the device in each evenly in the opposite corners until you’re happy with the surface tension.    With each professional canvas you’ll also receive a label to apply to the back of the canvas to help easily identify your work.