Four-piece set contains the most popular mathematical instruments: 12" ruler, 180° protractor, 60° set square and 45° set square. Tinted plastic provides excellent visibility and is ideal for students of higher math, drafting and engineering. Protractors and squares feature beveled center openings for easy sliding and pickup. Color(s): Transparent Smoke; Material(s): Plastic; Ruler Type: Standard; Standard Scale: 1/16".