In the NFT (Nutrient Film Technique) hydroponic system the system pumps nutrient from a base reservoir to a top-plate that contains your plants. That top-plate is at an angle to allow the nutrient to flow over the root-zone of the plants and back to the reservoir.
NFT systems come in many sizes. This makes NFT systems a great option for both small and large scale operations. The other major benefits of NFT hydroponic kits are that you don't have to deal with much growing medium. NFT systems can be sensitive to change in pH, however if you get on top of this you can generate excellent yields.