I bought this trap based on the user pictures which showed mice with four inch body lengths in the trap. However, this trap has never caught any rodents. Meanwhile, theAgri Zap RZU001 Rat Zapper UltraI bought at the same time regularly catches mice (usually only two inches long) using the same bait (peanut butter, nuts). I am guessing this is because the of the twisty windy tunnel of this model - I know I wouldn't want to squeeze through that. The other trap is just a big empty box, looks harmless.