Almost any kibble or kibble-sized treat works in the Hub, as long as it's firm and dry.
The maximum size of a single piece should be about 18 millimeters at its widest side
(about the size of a U.S. dime or smaller).
The Hub fills the dish by allowing a few pieces of food to fall through a small opening, so if the food you're using is large, sticky, or crumbly, it may not dispense properly.
If your dog isn't into kibble, or eats a raw diet, you may find that using freeze-dried or dehydrated meat works well. Chopped up veggies or Cheerios are also popular low-calorie alternatives to kibble.
Some specific brands recommended by our customers:
Zukes Mini Naturals
Fruitables Skinny Minis
Stella and Chewy Meal Mixers
Best Buddy Bits
Vital Essentials Freeze Dried Nibs
Pet Botanics Training Reward
Wet Noses Little Stars
Primal Jerky Nibs
Hill's Science Diet
Instinct Raw Boost