Water Brick booster seat

� Durable and comfortable � Made of Polyester and Neoprene � Lifts user 4" and enhance the effect of the massage for smaller people or children. Must be filled with washed gravel or marbles before use. GRAVEL OR MARBLES ARE NOT SUPPLIED.� Lifts user 4" and enhance the effect of the massage for smaller people or children. Must be filled with washed gravel or marbles before use. GRAVEL OR MARBLES ARE NOT SUPPLIED.