material : high quality plastic . functionality : medium weight supportive . excited when reached . heavy . able support eighty kilograms , sponge ok , neck supporter ok , the only one problem in the waist area screw hole , spring does not work after screw in then so not perfect ( in that way I am gonna be a hammer in that screws since the hole another side does not match with any screw size that provided ) . anyway , still satisfied .####[([0], [2, 3, 4], 'POS'), ([4], [2, 3], 'POS'), ([6], [8, 9, 10], 'POS'), ([19], [20, 21], 'POS'), ([23], [24], 'POS'), ([26, 27], [28], 'POS'), ([36, 37, 38, 39], [33], 'NEG'), ([41], [42, 43, 44], 'NEG'), ([67], [70, 71, 72, 73, 74, 75, 76, 77, 78], 'NEG')]