The Supply van is a mini-game where the player has to craft different items and hand them over to visitors while they come and go. 

Supply van usually comes around once a day. You can find it next to your shop and notice a special Supply Van icon in the upper-right corner of your screen at the main screen.

Supply Van gives you an amazing opportunity to select different rewards, including tonic drinks that help you instantly recover all of your preppers after a supply run (which is a great thing if you need to get them ready before the Town Defense).

Get ready to take advantage of these new resources and enhance your survival experience!