Gotrick Wood Panel 12X48,: A 3 Mm Russian Birch Surface Cradled On A Wood Frame. Although Priming Is Not Necessary For Some Applications, The Panel Can Be Primed With Gesso. Wood panel - 3 mm russian birch surface cradled on a 7/8 in. thickness traditional wood frame - Can be used with all painting and drawing mediums - Although priming is not necessary for some applications, the panel can be primed with gesso.