The two-piece foundation made it possible to bring a queen-size bed foundation up a staircase with a 90 degree angle turn during a move. It was impossible to bring up the original one-piece queen-size foundation and it had to be discarded. This two-piece foundation fit perfectly into my queen-size bed frame (which had to be dismantled and rebuilt to get it up the stairs). If you have a narrow or curved staircase, this is the solution for you!