Bill Robinson vinyl window pan sill ???

In Bill Robinson’s video “Retrofitting a flange window”, he uses a vinyl material with a foam backing to make his sill pan. Does anyone know the trade name of the material. I found Dura Flash that he uses for the vinyl flashing, but can not figure out what the material is for the sill pan. I’ve asked Menards, Home Depot, and Ace Hardware. They didn’t even know about Dura Flash. Our windows are coming in a couple days and my husband and myself are anxious to get started.
Replies
It could be Dupont Flex Wrap and if it isn't Flex Wrap is a great sill pan material. You'll have to go to a real lumber company to buy it though.
Marlene
Go ahead and use the flex. flashing mentioned-to get the slope to the outside-fit a pc of beveled siding on the sill plate b/4 flashing. Make sure you have enough R.O. in height.