Hi Tin,
Yes - it raises up and down. Raised up to the level of the top of the bath, the flaps on either side rest on the sides. It has 4 suction cups that fit it very securely to the bottom of the bath, and its very steady. Mil is only little, so we bought a portable, non slip 'step' which Mil stands on, with her back to the seat - this allows her to sit down, with her bottom well onto the seat itself. Once she is on it, I simply lift her legs up, over the sides and into the bath - we fitted a grab rail on the wall side of the bath, because although there is no way she can fall when on the seat, it just adds to her feeling secure. It lowers slowly, and when its fully down, the back rest tilts back - not flat, but to a comfortable angle. When down, her bottom is still around 4 inches off the actual bottom of the bath, but its low enough for her to be fully submerged into the water. Its rechargable battery powered, with the battery in a detachable control unit, really simple to charge and use - we powered it up for about 6 hours first time we used it, and we recharge every second use now for about 1 hour. Its possible to fit a waist strap, if needed, and its also possible to lower someone onto it with a hoist - so its hopefully going to be useable long term
. Once she is out, I lower it again, give it a spray down with bathroom cleaner, and wipe, detach the battery, and the back lifts off first, then just lift the base, and take it out. Its not that heavy, so its easy to put together and take apart, and lift in and out. For us, its ideal at the moment, and looks like it will be even with the probably future mobility decline. I was pleasantly surprised at the price, fully expecting something like that to cost over £400 - its already been well worth the money