If you own a Hammerli AP20 air pistol, this refillable air tank will give you the air you need to keep sending those pellets downrange! And with a maximum shot capacity of 140 shots, you can get a lot of rounds downrange between fills. The AP20 is known as a very affordable top-of-the-line air pistol. So why not use some of the money you didn't spend on the pistol to buy an extra air cylinder or two?