Here is another cat toy that mentally stimulates your kitties while slowing down their eating pace. The Rainy Day Puzzle & Play Cat Game has 14 hidden compartments and stimulates her natural foraging instincts. It has no removable parts, so you can let your pets play with its with peace of mind.
This puzzle holds up to 1/4 cup of food. You can adjust the difficulty of the puzzle as your kitties learn. More information is available here.