I have used this pump for 2years , it broke i fixed it, it also needed to be greased . I have had 6 other hand pumps they all broke, none could be fixed .including DR. Kaplans who said i was trying to rip him off. this the best, this does work, but it will take you time If you are wondering. 3 inches in 4 years i also use olive oil think about it you can eat it, i am 63