Amazingly we have never come across any reports on this extremely clever gadget in motorhoming magazines. What it does as act as a P or S trap but without any of the bulk and space requirements. It also solves the problem of smells coming up through the bathroom waste when rough roads cause the water in the P trap to shake out. The new trap is made by Heppworth Engineering in the UK and comes in under $30.00 from larger plumbing supply centres. It is an in-line fitting and is really just a long union. The operating principle is very simple. Water passes through a membrane which is normally flat. Peas etc. seem to pass through OK. Winnebago are using them on their shower recesses on all 2003 models. This has allowed far more design freedom with regard to grey water tank height - just about the best in the business!!! The photos below were taken in Ray Fountains custom built motorhome. The one on the left is from a kitchen sink. The photo at right is on a hand basin and amazingly shows a unit installed horizontally as is done in the Winnebagos under the shower. We have used four of these gadgets with absolutely zero problems so far (no special precautions made to stop naughty bits going down the plughole!!!)