These hozelock advanced pressure compensating drippers are for use at the end of the line and always give 4lh water flow regardless of their position in the system the drippers are made from tough uv stable plastic and have an in built filter they automatically self clean and automatically shut off when pressure is below 1 bar ideal for hanging baskets troughs growbags borders greenhouses cloches and vegetable gardens use at the base of small plants secure with a stake suitable for 4mm and 13mm