How do you make specific amount of sentry’s drop items

I need help on this on my map

Go to the sentry’s settings, go to the Knockout tab and set the amount of an item you want it to drop.
You can’t make it drop more than 1 Item Type (I don’t mean Item Amount) but you can use Item Granters for that to make them drop more.
(i.e Snowball Launcher and Quantum Portal)