REFRACTORY CASTABLE & GROG (3-items)(: REFRACTORY CASTABLE. REFRACTORY GROG SIZE : 3 MM TO 8MM MADE FROM REFRACTORY BRICKS CONFORMING TO IS : 8/1994 ALUMINA AL2O3 NOTLESS THAN 38%. BULK DENSITY : 1.4gm/cc GRAIN SIZE : 3 to 6mm (40%) 6 to 8mm (60%)