We launched this silicone bellows for grinder coffee It can perfectly fit for single dose hoppers, you can use immediately after simple installation It could also effectively clean the residual coffee grind after brew coffee or changing beans food grade, & stretchy which are could thousands of times Just step to install this single dose hoppers bellows without tools Once all the beans are ground, quickly press the bellows to out the residual coffee grounds It is suggested to cycle 2-3 times grinding & pumping Just press the silicone bellows for single dose hoppers with hand to generate sufficient air pressure Increase the utilization of, make full use of the last grind, and improve the taste of coffee