Product Features: Aesthetic, efficient, and non-toxic. Made of high quality crystal glass, one of the best supplies for the ecosystem of aquatic creatures, such as brine shrimp, amono shrimp. Use: Put in protein based bait such as dead fish, shrimp, meat, etc. Stick the trap into the aquarium let it filled up with water then put the lid on. Its crucial to make sure that theres no air bubble in the trap. So you can place the trap horizontally at the bottom of the aquarium with the holes facing down. We would suggest you remove the trap from the tank within two hours before the worms escape from the trap. Packing: 1 planaria trap leeches catcher Approximate Size: 2 Holes: 4.7 x 1 x0.5 inches (12 x 2 x 1.5 cm) (L x W x H) 3 Holes: 4.5 x 1 x0.5 inches (11.5 x 2 x 1.5 cm) (L x W x H)