These Strong, Watertight, Multi-purpose Plastic Garden Trays Are As Used In Our Self Watering Tray Kits But Can Perform Any Number Of Useful Garden Tasks. The Square Trays Can Be Useed For General Fetching And Carying, Are Ideal For Moving Seed Trays About And The Larger Versions Can Be Used With Gravel Or Sand And Soaked With Water To Aid Watering And Increase Humidity In The Greenhouse.as Used In Our See Self Watering Tray Kitsjumbo Tray 40cm X 117cm X 5cm (16\" X 46\" X 2\")giant Tray 55cm X 120cm X 5cm (21\" X 47\" X 2\")square Tray 59cm X 59cm X 7cm (23\" X 23\" X 2\")see Extra Value Packs Of Two And Save Up To 3