A loss circulation material (LCM) testing apparatus includes an LCM testing cell. The LCM testing fluid is a slurry of LCM material and a wellbore drilling fluid. A fluid flow pathway within the LCM testing cell is defined between an inlet and an outlet. The LCM testing cell includes a disk member that is removable positioned in the fluid flow pathway between the inlet and the outlet of the LCM testing cell. The disk member includes a disk base and a plurality of downstream-directed extensions, which combined define a plurality of flow openings. A method of evaluating a loss circulation material (LCM) includes introducing a LCM testing fluid into the LCM testing cell and detecting an amount of LCM testing fluid traversing the LCM test cell.