Add a slip on canvas roll up to keep it rolled up and off ur lap while you're are diamond painting. With this diamond painting canvas helper,you will never lose control of your canvases again! Holding your diamond painting together perfectly; It's a good tool to have in the diamond art accessories collection. The inner diameter is approximately 60 mm. Keep canvases of all sizes in check. JILINWEI Diamond Art Canvas Roller Holder,Diamond Painting Canvas Roll Helper,Pink Diamond Art Accessories Tools For Organizer Diamond Canvas