Robust frame fitted with an upper platen with spherical seat that moves vertically sustained by a spring. The apparatus can be placed and centered directly on the lower machine platen. The 50-C9030, conforming to EN 196 is designed to test portions of 40x40x160 prisms broken in flexure, while the 50-C9032, conforming to ASTM C109, fitted with compression platens 75 mm dia., and a vertical daylight of 53 mm is used to test 50mm/2” cubes and other little samples as, for example, microcores.