There are two main types: traditional humane cat traps and drop traps. The first is the most common and looks like an oversize cat carrier completely composed of metal grates. The bottom gets layered with newspaper to make it more comfortable and to absorb waste. Food is placed at the back as bait. At the center of the trap is a trip plate, which triggers the entrance door to close once the cat walks over it. Sometimes a few pieces of kibble are placed at the opening, as well, to lure the cat inside.