Very good product which works well but a little pricey. I am using it to keep my small "header pool" filled with water on a waterfall for a fish pond in the garden. Previously it used to syphon back into the main pond when the pump in the pond was was switched off. However, if like me, you are using it with a 38mm (1 1/2 inch) hose you are advised to remove the smaller 1 inch end pieces. This is easily done with a fine-bladed hacksaw.