The Artbin Slim Line Magnetic Case has a strong magnetic sheet adhered to the bottom of the slim case which holds metal objects in place. We've found it especially useful to hold metal blades (X-acto blades for example) and for making your own watercolor travel palette with metal pans. (pans sold separately under item # BL44949) Fill the pans from your tubes of watercolor and arrange the colors however you like! Take only the colors you want to use that day. The clear plastic cover will allow you to see contents inside and can be used as a mixing area for your watercolors if you're using it as a palette. It fits easily into pockets, tote bags, or larger storage cases but is just spacious enough to fit a travel brush in. Overall size: 7 3/8" x 3 5/8" x 11/16".