Bath/shower/wc seat for adults "Aquatec Ocean VIP"
The Ocean VIP is interesting because it has several positioning options for people who do not have a lot of body support (ALS, myopathy, MS, tetraplegia, BMI, etc.): chest strap, chest pads, headrest , seat rocker... including a foamed seat cover essential given the rather hard standard seat (see downloadable doc below). Its adjustable height is appreciable.
There are different models from several suppliers. The choice will depend on the dimensions of the bathtub, the budget and the options offered. Some models offer a rotating disc to facilitate transfers. Possibility also to provide side supports, a headrest and a thoracic belt for users with little trunk control.