Made from heat-resistant PET material, compatible with heat mats and grow lights operating within the temperature range of 0 to 120°F. The base tray is transparent, allowing direct observation of plant roots, so you'll know when the seedlings are ready for transplanting. Each cell tray has 12 cells, enabling you to cultivate multiple plants simultaneously, saving you time. Our seed starter kit makes it easy to start your gardening journey. Each seed starter tray is equipped with adjustable ventilation, allowing you to control humidity within the mini-greenhouse for different growth stages. Additionally, each cell tray includes drainage holes to eliminate excess water, effectively preventing root rot and enhancing seed germination and survival rates. Note: our lid design allows for convenient removal for watering your seedlings. Use a rubber band or small binder clips to secure the lids tightly if desired.