The plant starting trays are made from Silica gel material that is heat resistant up to 120F, suitable for heating pads and grow lights, and strong enough to be reused multiple times. PERFECT SIZE AND CONVENIENT TOOLS - Seed starting trays provide plenty of room for your plants and act as a barrier for seedlings, preventing damage from wind, rain or cold weather. Suitable for planting various vegetables, fruits, flowers and other seeds. Adjustable Humidity and Airflow - Turn the ventilation knob to control interior humidity from 50percent -100percent for seedling growth. The clear lid of the seed kit allows light to pass through and keeps warmth and moisture in to successful germination, especially suitable for seeds with high humidity and temperature requirements. Clear Cell Tray - Clear cells help remind you to water as needed, provide a better growing environment for seeds, and monitor root growth at a glance to are strong enough for transplanting. In addition, the drainage holes of the seed germination tray can effectively prevent over-saturation of and improve seed viability. How to Plant - Plant a small garden with your children and experience the joy and sense of accomplishment of planting. First, fill the seedling tray with nutrient soil (fill 2 or 3 full of soil), and then put the seeds into the hole. The third step is to with a layer of soil and then water it. The final step is to place the lid on top and adjust the knobs to control humidity and airflow as needed during the germination process. Colour:Black Material:Silica gel Package Contents: 8 x plant starting trays Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.