You have to setup and build the trap yourself. Everything went fine with the build until I had to setup the connection between the plate spring and the trap door. The metal hook had to be bent to get into the loop on the trap door mechanism. The plate that springs the trap is not sensitive enough. I baited the trap with some chicken bones and noticed that something had gone into the cage. It pulled the bones outside of the cage without springing the trap.Bottom line: so far the trap has been ineffective and I would look elsewhere for a better trap.