Adjustable Humidity: Equipped with integrated vents, these humidity domes allow precise control of internal moisture levels, ranging from 50% to 100%. Tailor the humidity to match your plants' growth stages, ensuring optimal air circulation and creating a healthy environment for rapid growth. Perfect Fit: Measuring 21.6 x 11 x 4 inches, these humidity domes for plant are an excellent match for standard 10 x 20-inch seedling trays. Warm Tip: Be sure to confirm the dimensions of your seedling trays before purchasing to ensure a proper fit. Thickened & Durable: Crafted from high-quality, thick plastic, these humidity domes for seed starting are designed for long-lasting use. The sturdy material not only resists environmental hazards but also fosters a warm, stable atmosphere to enhance seed germination and support healthy seedling development.