This large-scale polarizing filter stress demonstration apparatus shows stress patterns on different solids. Includes 4 clear acrylic pieces of different shapes that can be placed between the polarizing filters and squeezed to produce different observable stress patterns. Each filter has an 8-inch diameter and is mounted in a high-quality wooden frame measuring 10.5 x 5 x 2 inches. Comes with an instruction manual. A valuable tool for determining critical stress points in transparent materials. Suitable for physics classroom demonstrations of polarized light, photoelasticity, and material stress analysis.