Premium & Durable Material:Our air stone is made of high temperature sintered quartz sand - extremely sturdy, completely non-toxic and safe for pond and aquarium. Ideal for 4mm or 8mm air hoses. Perfect for reliable and long-lasting oxygen supply Optimised oxygen distribution: Through fine-pored air diffusers, the stone produces particularly fine and dense bubbles. Greatly increases the oxygen content in the water, reduces CO₂ and thus supports healthy life for fish, shrimp and plants Quiet & Stable Operation: Flat design for safe positioning on the bottom and minimal noise generation. No disturbance for aquatic inhabitants - only harmonious and silent bubble performance EASY CARE & CLEANING: For long-term use, we recommend soaking stone for 1 hour before first use and brush monthly under running water. This maintains consistently high performance - without obstructions or loss of effectiveness VERSATILE APPLICATION:Whether garden pond, breeding plant, hydroponics or aquarium - our air stone is ideal for freshwater and saltwater applications. The perfect solution for demanding aquarists and pond management