The Water Brick Water Seat also serves as a more comfortable spa seat alternative while increasing the seat height for shorter spa users. Made of PVC coated vinyl, the Water Brick is well suited to the spa environment. At over 4 inches thick, the water seat offers great comfort compared to sitting directly on any spa surface. To ensure the seat sinks into place, a removable pouch has been included which can be filled with marbles or washed gravel to increase the weight and/or height of the water seat. The spa experience is meant to be relaxing, let the Water Brick complete the experience.