There great for catching american signal crayfish. There easy to catch just puncture a tin of cat food with an old screw driver or something similar a few times to let the scent leak out then put it in the trap. The weight of the tin will help keep the trap on the bottom as well. You will catch more crayfish on a night than during the day. Then just boil them whole for about 15 minutes. when cool take out of there shells and enjoy with large amounts of real ale