and at the time of w c m's invention back to prevent us from know that there were problems one of those problems is that because of the size and rigidity evaluating back over veterans as to how effectively they seal at low pressure it's a difficult test to pass first requires the back door preventer seals and six inches of water which is less his answer starting at one twenty well i would answer that by saying the point at the very very start it's a point at the very very start of located pressure at some point it will stop any leak it has got to be a point and actually this was on cross examination that he was asked this question and in this test there was a clear to where you can see primus black or backflow preventer inside and act normal conditions under normal engagement the freestate where there was no pressure it's a very very thin ceiling line around this to it's at some point all the way around the edge of the in some of the two would you call that point seen yes later on if he's describing the test shows at six well there may be a residual but there's no back pressure at that point but he went on to discuss and get a one sixty six  when before we get there at the very bottom of one sixty five is when he started to talk about the six inch water pressure a one sixty six he's talking about the results at twenty four inches  water and outline eight where he's asked what are the results of twenty four inches of water line he says approximately the same as the six inch you can see that right behind the lip that little that it's only also a one sixteen gauge on redirect he was asked with respect to your testimony about the face and is it your belief that before the prior check the face that it was that it must to on this device is that progress device what was unique about it is that it has this first outer surface that extends outwardly and it normally gauges the to when in when pressure comes in it bends in wordly which against the wall and we believe that the court's construction of point sealing mesh not only conjured contradicts the language of the crime but it also excludes that prefer the claim on its face only requires that the pointed ceiling edge normally engage the inner and outer housing when it talks about sealing engagement it talks about the lip portion as a whole pressure at that point so it's sealing in its normal state to prevent any ticket whatsoever under bacteria pressure conditions you have inflow pressure coming in normally at sixty fiesta and just th raising of a hoax can create back pressure that potentially can contaminate the water supply even at a quarter per square inch of pressure and in that condition neuron was referring to is really shown in in on page twenty three of the court's decision and that is in fact the same if you can manage that that is not going to see the image but that forms a band which contacts the the outer wall at that point or that at that area it's a band it's not a sharp point if you are in the in the claim and even it even the house ok and nor is nor do you have a lip portion which has a size and shape from it to deflect or the axis of the housing when and all the rest of that  now that last clause invites opens a careful reading of the specifications when it is that kind of almost means plus shape you know the judge blackburn's had a construction in his opinion that would require that trying a portion to be the planet earth had decried that said it's not significant but when you say that that's not significant then put you do things just regard when you're black letter law that every drive which was not easy that vertical flat flat our surface cassidy that flat plane forty eight and these we know that that have to bear against the water pressure intrinsic ordinary meaning of the term  and he said as set forth in the claim between the first and second fluid pipes and then he also said that anything connected to the laterally extending pound it will necessarily be these two but on the planet this construction hot here cold here and then the mantle of pike which could extend i don't know fifty or one hundred yards whatever house whatever house monitors and that type of the mixing there was much disagreement her vertical to be perpendicular otherwise it would have no meaning in the doing there are other factors disputes about how it's operated which we've already talked about there's a fact views as to whether or not their point actually says we believe that the moving on the last point about the fluid actually conduit we don't believe there's any limitation to limit cla