Hydrofarm  AS4FLEX 4-Feet Active Aqua Flexible Air Stone
This permeable flexible air stones are a great way to aerate your growing system. The flexible stones bend into any shape you need to deliver air where you need it most, they also create less back pressure than traditional air stones, which reduces damage to your pump. This product weighs 0.4-pound. Measures 10-1/2-inch length by 3-1/2-inch width by 1-inch height.