I wasn't able to find anything on 'Da Flex St250' with a quick Google search.
Is it a non-sticky highly deformable material, like some sort of closed-cell sponge (is that an oxymoron?), or is it more similar to mastic tape? (3M branded tar, useful for weatherproofing electrical connections
)
Oh, and for the really important question
: what context is your use of que from? Is it pronounced 'queue' or 'kuh'? I know it's a word in the so-called 'romance languages', but I've never seen it capitalized before.