Universal trap simplifies the removal of various unwanted aquarium inhabitants. Automatic trap with dual entrances features a funnel entrance for bristle worms and a larger entrance with one-way curtain for crabs, snails, mantis shrimp, and more. Simply place baited, heavy-duty plastic trap in your aquarium and remove when desired target animal is captured. Measures 6.5" x 3" x 3.5" high. For fresh and saltwater use.