This kneeler comes pre-assembled. All I had to do to unfold the legs. It 17.5" tall (from the ground to the bench seat) or 3.5" (from the ground to the kneeling pad).
I frequently flip it from the bench to the kneeler, so I removed the pockets from the rails because if you flip the kneeler you need to attach the pockets to the other end otherwise so they don't drag on the ground.
The pad are fairly soft, I like how the feel on knees.
To fold the kneeker I use my hand to depress the lever on each side. Otherwise the bench is locked in (which is a good thing for the person who is sitting on the bench). When folded the kneeler is 23.63" Long x 10.63" Wide x 5.32" High.
Amazon has about a dozen sellers selling the same kneeler, I selected this one purely based on price. Amazon prices vary often so price compare!
It is exactly what I hoped for, it is making working in my garden much easier!
You can find it on Amazon by following this link.
Ali Julia review ★★★★★