First of all, IT HAS 9, COUNT 'EM, 9 LEGS!!!!!  And, the supports are across and not length-wise to the mattress!!!! And, and, and those legs screw into the frame, to hold the size, but not just slipped onto the cross-member of the frame.  AND, last but not least, the frame itself is very sturdy whereas, I can barely feel the mattress move when my wife gets into it....!!!!!!