See-Thru Dressmaker's Ruler 4" X 15" (10.2cm X 38.1cm) Parallel slots for precision markings from 1/4" to 3-3/8". For more accurate markings. be sure pencil point is very sharp. Measure and mark exact location of buttons, buttonholes, pockets, etc. Measure straight of grain from fabric selvages. Measure and mark spacing for pleats and tucks. Mark guide lines for decorative stitching. Simplify pattern alterations. Guide tracing wheel and pencils markings. Measure and mark bias strips. Draw guide lines for undercollar padstitching.