Features: Sintered by high temperature. Durable & washable. Different from other air stones. Direction for use: Connect the air stone with air tube. Soak in the water for 15 minutes before use. It�s durable and be used for a long time. When it is clogged with dirt or producing bubbles with low quantity, please wash it for re-used. Product Specification: Model: Carborundum Air Stone B-10066 (6cm) Gas Output: 5 L/min Spec: 60 x 46 x 5 mm