1313-1 Size: 18" Features: -Safely cut paper, matte board, and foamcore with a raised edge and groove that protects fingers while cutting with a hobby blade. -Photo-anodizing imprint technique makes the calibrations a permanent part of the aluminum that will never fade or rub off over time. Dimensions: Size 24" - Overall Height - Top to Bottom: -0.25". Size 24" - Overall Width - Side to Side: -1.6". Size 24" - Overall Depth - Front to Back: -24.5". Size 18" - Overall Width - Side to Side: -0.5". Size 18" - Overall Depth - Front to Back: -18.5".