This Pest-Stop Little Nipper mouse trap has a unique treadle design, which makes it one of the most effective traps available. The Little Nipper was first made by Procter Bros. Ltd. in 1897, and its distinctive design has remained largely unchanged ever since. Bait is placed on the treadle, which is raised when the trap is set, and the mouse has to cross the treadle to reach the bait. The slightest motion is enough to trigger the trap, delivering an astoundingly high catch-rate. Quick and humane.The PRCPSLNM Little Nipper mouse traps are supplied as a box of 30 traps.