After my mom fell off of her bed a couple of times, I decided that I needed to purchase a bed rail for her (whether she wanted one or not). And, since she had a king size bed, I also needed a rail that could cover enough of the bed, so that she wouldn't slip past the railing (or that the rail wouldn't easily slide away from the bed). Thankfully, this is the bed rail that I purchased on the first try. While even at it's shortest setting the rail is wide enough to cover quite a bit of the bed, I can still extend it if I need to. Plus, the bars that slide between the mattress were quite stable even without the use of the strap--the king size mattress was too heavy for me to maneuver. (Don't worry, I tested the rail before I allowed my mom anywhere near it, if it can sustain my pulling, it will definitely not budge when she uses it). This item was easy for me to assemble, and worked like a charm. Need I say more?