This is a drip tip for irrigation, adjustment of water flow is made with a tapping screw. Adjustable from few drops to many literl/hour. It fits 4mm inner diameter tubes, very tightly to avoid popping out with pressure. It helps a light heating with a lighter to soften the tube, exprecially older ones hardened by sun heat. A 3mm tapping screw (preferably stainless steel as it doesn't rust) is just screwed in the center hole to adjust water flow. Use pointy screws as the point will get in the inner hole and give a finer water flow adjustment...

I created these links where you can find all common filaments and spare parts at the best prices. These are just links to selected eBay and Aliexpress items, where I normally buy spare parts and materials for my printer, prices are excellent and products are good. If you buy something from here you will support me a little bit to make these projects.

1Kg PLA Filament - eBay