TG67 Circular Compression Cage This fixture consists of a 50 mm (1.97 in) diameter circular compression cage for test machines operating in tension and compression or tension only. Can be used with thermal cabinets testing at temperatures up to 300C (572F). Maximum sample diameter 50 mm (1.97 in). Capacity: 20 kN, 4496 lbf Packaging: Complete compression cage fixture. Applications: Used for general purpose compression testing of a wide range of materials and finished products.