Like others have said, more useful than the sale name indicates.
Since I do a lot of scratch building of old kits, I wish Estes would add the BT-56.
Tubes, Nose cones & Engine Mounts are al available as well as many plans.
My first Estes Camera Rocket was a BT-56, an E2X kit that used 110 film.
I still have film in that cone that needs to be used up and developed.
Even if Estes has discontinued the BT-56 line, that size is a huge portion of it's history.
And I like building the old kits I had when I was a kid from scratch as close to what they were as I can.
So PLEASE ESTES, Add one for the BT-56!!!