6 inch ruler with 1/8 inch marks. The numbers and marks are lightly inset so you can just take a marker or paint and drip it in so they never rubbed off. The edge has been slightly chamfered off so you do not have the bumps as you draw on that side of the ruler. The ruler is exactly 6 inches long so no need to measure in from the side to get the right measurements. Also 4 inch slot in the inside for a straight line mark. the slot lines up with the 1/2 inch mark and goes to the 5-1/2 mark. The ruler is 1/8 inch thick and 1.5 inches wide.