I had a very large adapter to plug my vacuum cleaner hose into the skimmer of my swimming pool. And it finnaly broke (UV?). So I designed this smaller one.It consists of two opposed cones, so they just plug in a standard 40mm pool hose (well, that's a standard here) and on the other side to the bottom of the skimmer (which is probably not standard!)Update: you may prefer to use the service described at http://www.thingiverse.com/thing:26096 to generate STL files for your own diametersBy the way, it proved easier to handle than the stock one b/c the whole tube end is below the water surface in the skimmer.First of all, check the flexible tube and skimmer bottom diameter.The openscad file here is set up with:There are (probably useless) internal structures for added rigidity. Well, they also make the thing more interesting to print! ;-)By the way, make sure there is a filter before your pump for large objects ;)