The feeder cup has a clear plastic, removable lip that prevents the roaches or worms from getting out, but they are shallow enough that the dragons can easily get to them easily. Most important, since the lip plastic is clear, the dragons can see the worms or roaches on the bottom of the cup. The small Feeder Cups measure 3-1/2 in diameter by 3/4 in height and the large Feeder Cups measure 5 in diameter by 1-1/4 in height. We recommend washing by hand to avoid damage. Carolina Custom Cages is a division of Carolina Designer Dragons, Inc. We like these Feeder Cups because they are functionally perfect in several ways. Since were feeding a specific number of roaches or worms per day to our dragons, we can be certain that the feeders dont get lost in the habitat and our dragons can find them readily. Also, we can monitor their appetite by easily counting how many have not been eaten.