dispenser of baginski et al are a the addition of a resilient bellows to the body of the dispenser which allows for the internal volume of the dispenser to be changed and b the addition of a centering feature to the base of the counterweight which enables the unseated valve to be positioned upright and centered on the dispenser opening and valve seat the benefits of these two improvements is explained hereinafter dispenser 10 has a substantially rigid body 12 and a resilient bellows portion 14 which are preferably injection blow molded as one piece from a clarified polyolefin or pet it is beneficial for the body to be clear so that the level of fluid additive may be observed from outside the dispenser when filling it to a fill line marked on the dispenser body 12 typically has a thicker wall than bellows portion 14 alternatively a separate pre formed bellows is connected to rigid body 12 in a fluid tight manner such as by adhesive or fusion bonding or by a gasketed mechanical fastening the material and construction of body 12 and resilient portion 14 must be able to withstand the heat of hot laundry water and detergent dispenser 10 also has an opening 16 for fluid communication with an internal volume 18 opening 16 is surrounded by an annular valve seat 20.