Refractory, CRM, Magnesia, set of 10 x 20 g (1 x 20 g each of JRRM-401, JRRM-402, JRRM-403, JRRM-404, JRRM-405, JRRM-406, JRRM-407, JRRM-408, JRRM-409 and JRRM-410), Powder