30 pcs Aquarium Supplies: 20 x Aquarium Air Valves & 10 x Aquarium Bubble Air Stones Creates bubbles in fish tank when connected to an air pump. Helps increase dissolved oxygen levels in the aquarium, supporting a healthy environment for fish respiration. Air valves are designed for aquarium use. Assist in increasing oxygen levels and maintaining fresh water conditions for aquatic life. Easy to connect with standard air tubing. Material: Plastic Inlet Diameter: 4.8mm / 0.19inch and 5mm / 0.2inch Size (approx): 3.9 x 1.3cm / 1.5 x 0.49inch (L*W) and 47 x 23mm / 1.9 x 0.9inch (L*W) Color: Blue and Gray Weight: 44g and 39g Product Name: Aquarium Air Valve Package Contents: 20 x Aquarium Air Valves 10 x Aquarium Bubble Air Stones Note: Light and display differences may cause slight variations in color between the image and actual item. Measurement may vary by +/- 1-3cm.