Apollo Horticulture Germination Seedling Seed Starter Tray with Humidity Dome 1 - Apollo Horticulture Seedling Starter Kit Dimensions: 21.25 50-cell Seedling Inserts with 2 vent points for optimal airflow Controls humidity under a 7.23 Package Includes: 1 - Dome Cover / 1 - Seedling Tray / 1 - Water Tray