WaterUps® Wicking Cells are modular in nature and are designed to be able to fit most garden bed shapes and sizes. Use these joiners to connect the cells together in the base of your growing area. Each pack contains 25 joiners. In way of a guide, you will need approximately 2 joiners per cell. So if you purchase 1 stack of 12 WaterUps® Wicking Cells you should purchase 1 pack of 25 WaterUps® Joiners.