This is the pump I use. I got it from AliExpress. They size from 1.75 x9 to 2.5 x 9 and 1.75 x12 to 2.5x12. You can buy the cylinders by themselves too when you need a bigger size https://a.aliexpress.com/_EG6cWUl from bigtitty killua leaks 9 Post