Received the bed today, a day earlier than expected, which was great! My husband and I put the king size frame together fairly quickly but you definitely need something to support the mattress with this frame. The picture showed it with horizontal bars that I assumed would come with the bed but the foundation was open with just one middle, vertical support bar. That is the reason why I only gave it 4 stars.

Tis frame was replacing an Ikea Fjell frame so we used the slats from that bed to support our mattress. Took a bit of cajoling but we got it to fit. It was also high enough for us to slide the drawers that came with our old bed beneath. I'll try and remember to post another review once we have had it for a while but right now we are really happy with it.