Right-angle triangle square with a resting edge, through holes of various sizes, elongated slots and a row of holes along the inclined side. It is a marking and measuring tool for technical drawing, carpentry, workshop jobs and DIY: it is used to mark right angles, transfer measurements and mark parallel or spaced lines. The flat shape allows it to be placed on the sheet or on the workpiece and the holes to be used as references for a pencil or the tip of a nail