This Gold Testing Kasoti Is A Small, Flat Stone Which Can Be Used To Test The Purity Of Gold Items. It Measures 2 1/2" X1 1/2"x 1/8". To Be Used With Gold Testing Keys And Acids (not Included).* 2.5" X 1.5" (6mm) * Compact Size * Use With Acid (not Included) * Test Gold Quality * Professional Quality