It’s a simple Spring water container to which I’ve drilled a hole in the base and fitted a 90mm PVC joiner to the neck.
I just place the gadget over any of the 90mm pipes that go through the mulch and in to the root zone and fill.
The filled container then drains slowly and deeply into the soil below the mulch, ensuring that there is a good reservoir of water there for the trees to drink throughout the Summer.
We have 2 of these devices and rotate them through the garden, from tree to tree. This way, no water is wasted. 10 litres or so delivered directly to plant roots by this method over time is much more effective than practically any other method of delivery.