This Hydro Flow? Drip Kit is designed to simplify your irrigation set up on 3 ft x 3 ft and 4 ft x 4 ft grow trays. From reservoir to plant, this kit provides all the irrigation components required to set your garden. Hydro Flow? Drip Kits are compatible with all 3 ft x 3 ft and 4 ft x 4 ft grow trays. Trays purchased separately. Kit includes pump, timer, plumbing and hardware for 12 sites.