Hello,
I gave two electric bicycles to a friend of mine that has 3 kids, and they destroyed the tires pretty quickly, as kid's are known to do. He told me about it reluctantly, and said that he was unable to find any tubes or other paraphernalia associated with the 26x4.0 size. I went online looking for a solid rubber tire, or some other new invention to prevent flats on these big expensive tires, and I found you.
He installed them, and so far all's good in the neighborhood. At least I haven't heard anything to tell me that they have another flat tire yet.