E57...and those of you too timid to ask...the crutch tip helps keep the handle from sliding on the floor when you are using it "shoe up."
If you are using just any old pipe for a handle, you want the 1" tips. If yours are the fancy store-bought handles, then the 1 1/8 tips fit (for the two smallest benders).
I also use Loktite to keep the head from unscrewing.
