I have a curious fitting on one of the outlet pipes of my power shower. It has no brand name, makers name or any kind of identifying features on it except a flow direction. It is a 15mm plastic tube through which the water flows and inside the tube there is a tiny metal torpedo shaped object. Attached to the tube is a circular box about 7cm diam with an aluminium finned lid showing flow direction. Inside the box is a small circuit board which has two pink wires connected which exit through the lid. Does anyone know what it is, does and where do the wires go?