．Size of bottom plate：15 × 6 × 1.5 cm
．For filtering and to cultivate nitro bacteria.
．Cooperating with sponge filter for optimum result ( 2 in 1 filteration ).
．Cooperating with sponge filter and rain bar unit for optimum result
(2 in 1 filteration and increase O2 content).
．Cooperating with mini hook-up and sponge filter for optimum result (3 in 1 filteration).