Used either for rapid determination of percentages of flat and elongated particles in coarse aggregate fractions of 3/8" (9.5 mm) or larger. Consisting of 8"x16" (203.2x406.4 mm) base plate with rubber feet, two fixed posts and a 12" (305 mm) pivoting arm, allowing ratios of 1:2, 1:3, 1:4, 1:5 to be obtained.