Hi. https://www.screwfix.com/p/jg-speedfit-plastic-push-fit-stem-coupler-f-22mm-x-m-28mm/42503 Hi Long story short...I need to reduce piping from a speedfit 28mm elbow to 22mm piping. Is this the correct product. I can't find any illustrations of this product in situ or explanation of it intended use. I assume that the male end slides into the twisting section of the elbow and a 22mm pipe slots into the other end of the coupler. I assume this is the correct product for reducing pipe sizes. I can't see anything else Thanks.