These easy-to-use instruments combine the functions of a t-square, triangle, transparent straightedge and protractor in one.  One of the most useful and convenient aids you will ever find for drafting, drawing, and nautical applications.  Gliders roll easily to make parallel lines but won't turn under accidental pressure.  Features durable clear acrylic with die-sunk graduations.  Ruling edge in inches (reading to 16ths) or in metric.  Eluxite satin finish aluminum grip bar and knurled rollers with non-skid rubber O-rings for smooth operation. Individually packaged with complete instructions.