This is the one I just bought. It’s a pretty good double sided magnet, with a decent weight rating. It also has two attachment points, so you can hang it from the top or the side. It comes with the magnet, rope, a grappling hook, and gloves
From what I’ve seen in my use (I haven’t had it long), I’d say put locktite on the screws to keep them in place, but it’s not necessary. Also, use some electrical tape or shrink tubing to reinforce the knot (it comes with a small piece of shrink tube but it’s not much). This could be said for any magnet though