SL-SF12 Spectacle Frame Torsion Tester Eyeglass Frame Twisting Fatigue Test Machine ISO12870 45 Degree Product Overview The SL-SF12 Spectacle Frame Torsion Tester is engineered according to the technical specifications of GB/T14214-2003 "General Requirements and Test Methods for Spectacle Frames" and ISO12870:1997 "Ophthalmic Optics - Spectacle Frames - Basic Requirements and Test Methods". This precision instrument clamps eyeglass frames securely at both ends of the jig for