These slats are just what I needed when I had to replace the slats underneath my Thomasville 4-poster bed.
The legs were difficult for me to push into the slats and I could not push them in far enough to keep them together before assembling the slats and screwing them into the bed. If the legs had been pre-attached to the slats, that would have been a real plus.
My king size bed has 2 twin boxsprings under the mattress. After checking that all the slats were level and putting the boxsprings and mattress on top, I found that when laying on the bed I had the slight sensation I was tilting off it. The 2 twin boxsprings both lay on the bracket in the middle that holds the slats together, raising the center of the bed a little. I found that I needed to measure the distance from the top of the bracket to the floor to ensure it was the same as the distance to the floor from where the slat is screwed into the wood shelf on the side of the bed frame. Without measuring this, the center of my bed was slightly higher than the sides, causing the boxspring and the mattress to tilt.
These metal slats are much lighter than those that originally came with the bed, but so far functioning as they should.