General Tools 843/1 Pencil Compass and Scriber COMPASS &amp; SCRIBER: Designed for marking contours, drawing circles or arcs ADJUSTABLE: Positive wing nut adjustment up to 8 inches RIGID: Full-length hardened steel pin in metal frame for greater rigidity and accurate scribing DURABLE: This pencil compass and scriber is constructed of brass plated steel VERSATILE: Can be used with most pens and pencils. Pencil not included.